major: a series of digital photodiode sensors (dpds) 1 ......the major-series of modules are capable...

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Germany & Other CountriesLaser Components GmbHTel: +49 8142 2864 – 0Fax: +49 8142 2864 – [email protected]

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MAJOR: A Series of Digital Photodiode Sensors (DPDS)

1. General Description 1.1 Introduction

LASER COMPONENTS is introducing a complete new series of digital pho-todiode modules: The MAJOR series. The MAJOR is a universal and powerful tool for OEM customers ready to be integrated into many environments. There-fore, the name MAJOR has been chosen since music is a universal language that is worldwide understood. The concrete photodiode material composition (i.e. the wavelength range) is expressed by a certain tonality. For instance, D-MAJOR is the code for a product line that uses carefully selected InGaAs diodes and covers the wavelength range from 500 nm to 1700 nm.

At the beginning, C-MAJOR (SiC, 220 nm to 365 nm), D-MAJOR (In-GaAs, 450 nm to 1700 nm) and E-MAJOR (Extended InGaAs, 450 nm to 2200/2600 nm) are available. The detectors have been designed for minimized responsivity change versus temperature.

All MAJOR modules are assembled into a M12 screw housing and all ver-sions are able to communicate via RS 232. The modules are based on the ACU2 module platform.

In General there are two groups of MAJOR modules:1. MAJOR with serial interface for digital chaining of modules (coming soon,

Forecast Q4/2013)2. MAJOR-A with analog outputs for photodiode and temperature values

(Available)

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The electronic in both groups is the same. Due to limited number of output pins in a M12 housing, only 8 of 12 available signals can be routed to the output connector. Therefore, those two general product families have been cre-ated. Later on, a third possible version for sending and receiving triggering impulses might be added to the product portfolio. While the first group is focused on single sensor applications - serving digital and analog sampling results to a host, the second group is focused on chained applications, where multiple sensors provide their sampling results digitally over one shared RS232 chained bus to a host.

When digital chaining is desired, there is no limit for the number of MAJOR modules in a chain and how long the chain gets as long as the distance between two sequential modules doesn’t exceed approx. 15 meters. This type of MAJOR module has two independent RS232 interfaces. Therefore they can be chained to each other and digital data can travel from one end to the other end of the chain.

The limitation in this type of configuration is the bandwidth. The amount of simultaneous data generated by several MAJOR modules has to share the available bandwidth given in the chain, which is 115200 baud maximum.

MAJOR-A modules have only one digital and one analog interface pairs. So they can’t be chained. But this type of modules provides the sampling result to the host not only in digital form, but also as conditioned analog values. The temperature is also available to the host as an analog value. One of the analog outputs is the conditioned sensor value, i.e. internal ADC input. A voltage that is correlated to the sensor temperature is the second analog output in the standard configuration. Theoretically, the second output can be any other value controlled by the firmware (user application programmable).

1.2 Features Small form factor (M12 housing 65 mm long) Complete integrated sensor signal conditioning and processing Including a 12-bit up to 200 ksps ADC with scalable dynamic range Sensor sensitivities up to 4 µV/LSB with auto gain capability Temperature and noise compensation algorithms Capable of storing sampled sensor data together with temperature and time stamps Providing digital and analog sensor data on its 8 pin interface Digital communication over RS-232 lines: sensor-to-sensor & sensor-to-host (PC) Two independent RS-232 channels for chaining of sensors Host independent intercommunication of sensors and actors in a chain Possibility to port and integrate user applications

1.3 Basics

The MAJOR-series of modules are capable of sensing, conditioning, processing and storing sensor data without additional or external processing power. Results may be compared to user defined thresholds for generating digital messages to the environment, storing them inside the sensor itself or shift them out directly to a host via its RS-232 interface.


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As shown in the block diagram, MAJOR modules are generally built with an internal fixed temperature sensor and a programmable analog front end for interfacing various types of sensors. An integrated A/D converter and a 16-bit µController together with 4 MB of Flash storage makes the MAJOR ideal for many applications in the industry.

Digital processing of the module is based on a 16-bit RISC processor with 16 MIPS, 128 kByte Flash and 10 kByte SRAM. The ADC module is a µController built-in peripheral with a 200 ksps fast 12-bit SAR analog-to-digital con-verter including a reference generator for sensor biasing.

The analog sensor signal gets conditioned by a programmable gain amplifier (PGA), which can be controlled by the firmware. It is then served to the ADC with the desired gain. At the same time an offset voltage can be applied to the system to blend out any unwanted signal levels or noises. The dynamic input range can be matched perfectly to the 2.5 V dynamic range of the 12-bit A/D converter.

The electronic is capable of a total trans-impedance gain of 1,28∙108 V/A. This gain consists of a trans-impedance gain part expressed by 10m V/A with m = 1 to 6 and a voltage -gain part expressed by 2n with n = 0 to 7. The voltage gain is controlled by the PGA over the firmware, while the trans-impedance-gain is fixed by a resistor dur-ing manufacturing time. In most cases a value of 104 has been chosen.

The digital Interface is built by a RS232 transceiver with three driving and five receiving pins. All pins are protected to ±8 kV using the IEC 61000-4-2 Air-Gap discharge method, ±8 kV using the IEC61000-4-2 Contact Discharge method, and ±15 kV using the Human-Body Model.

The analog outputs are capable of high-output-drive by CMOS op amps featuring 200 mA of peak output current while they remain stable for capacitive loads up to 780 pF. The output amplifier exhibits a high slew rate of 10 V/µs and a gain-bandwidth product (GBWP) of 10 MHz.

Sampled sensor data can be transferred to a PC as raw data – to databases or custom applications – or as user friendly verbose characters to be displayed on a PC using a hyper terminal. Any MAJOR module accepts user com-mands to generate various types of data outputs needed by the user.


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2. Example: D-MAJOR-17-3000-1.0-A

2.1 Details of the photodiode

This module with digital and analog output does use a panchromatic IG17X3000 photodiode as sensor element. This diode is a 3 mm InGaAs PIN photodiode with a nominal wavelength cut-off at 1.7 µm and has been designed for demanding spectroscopic and radiometric applications. It offers excellent shunt resistance in combination with superior responsivity over a wide range. The responsivity change vs. temperature is less than 0.1% relative change per Kelvin over a wide spectral range. (Note: IG22 diodes do show a relative change, which is still lower by more than an order of magnitude).

Features 50 % Cut-off Wavelength ≥ 1.65 µm Typical Peak Responsivity: 1.05 A/W Excellent Temperature Stability Reduced Edge Effect

Applications Spectrophotometer Diode Laser Monitoring Non-Contact Temperature Measurement Flame Control Moisture Monitoring

Electro-Optical Characteristics, Specifications @ 25°C

Part Number Diameter [µm]

Shunt Impedance (RP) @ VR= 10 mVb [MOhm]

Dark Current (ID) @ VR= 5 V [nA]

Capacitance (CS) @ VR= 0 Va [pF]

Forward Voltage [V]

Min. Typ. Typ. Max. Typ. Typ.

IG17X3000G1i 3000 3 15 20 200 1550 0.73

Equivalent circuit

ID Dark Current IPH Photo Current IR Noise Current CS Shunt Capacitance RP Parallel Impedance or Shunt Impedance


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Spectral Response

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

450 650 850 1050 1250 1450 1650 1850

Resp

onsi

vity

(A/W

)

Wavelength (nm)

-40C -20C 25C 65C

Typical

Photosensitivity Linearity

92

93

94

95

96

97

98

99

100

101

0 5 10 15 20 25

Rela

tive

Sens

itivi

ty (%

)

Incident Light Level (mW)

Typical, Wavelength = 1310nm

IG17X3000

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Shunt Resistance vs. Temperature

1,00E-01

1,00E+00

1,00E+01

1,00E+02

1,00E+03

1,00E+04

1,00E+05

-40 -20 0 20 40 60 80 100

Shun

t (MΩ

)

Temperature (°C)

Typical, Vr = 10mV

IG17X1000

IG17X2000IG17X3000

IG17X1300

Current vs Power Density

1,E-09

1,E-08

1,E-07

1,E-06

1,E-05

1,E-04

1,E-03

1,E-02

1,E-01

1,E+00

1,00E-04 1,00E-03 1,00E-02 1,00E-01 1,00E+00 1,00E+01 1,00E+02 1,00E+03 1,00E+04

Curr

ent (

A)

Power (W/m²)

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2.2 Module Operation Mode

There are two common operation modes for a photodiode detector. The MAJOR module series are configured in Photo-Voltaic mode, means UR= 0 and therefore ID= 0. The capacitance CS is also larger when no external biasing voltage is applied. Although this mode has slower response times in compare to the photodiode mode, it tends to exhibit less noise, resulting in more precise measurements.

Independent of selected detector, the electronic of MAJOR module only observes the voltage over the load resistor RL. The blue line shows where the RL is configured in standard modules.

The incident radiation generates a photocurrent I_PH loaded by diode characteristics and an external load resistor RL. When RL << RP (at least factor 1000) then other parts of the equivalent circuit like parallel capacitance CS and shunt resistance RP are negligible leakages and together with the noise current I_R are ignored in MAJOR standard mod-ules. The ADC in the MAJOR module measures the shunt resister voltage expressed by RL ∙ IS after conditioning it. The maximum shunt resistor voltage value has to remain below forward voltage of the photodiode, which is declared at 730 mV for the IG17-series of photodiodes. The limit chosen in MAJOR module for observing RL ∙ IS is at 500 mV.

2.3 Module Characteristics

Standard MAJOR modules are optimized for measuring weak signal intensities. Considering the 500 mV as the maxi-mum dynamic range for the detector output and a built-in shunt resistor of RL=10 kΩ in the standard MAJOR modules, results in a dynamic light intensity range, which shouldn’t exceed photo currents over IPH = 50 µA. Both, the “Photosen-sitivity Linearity” and “Current Power Density”, curves show in these lower ranges absolute linear relationships.

All the negligible currents explained before including the noise current IR together with unwanted ambient incident light generate an unwanted total current through RL, generating an unwanted noise voltage in front of the MAJOR’s ADC input. This voltage can be compensated with a software controlled offset voltage Voffset to hide it completely from being measured and wasting the dynamic range of the ADC input.

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Depending on application needs, the user can now zoom into an area for measuring sensor values by applying related gain and offset voltages as shown in figure below:

2.4 Latest MAJOR modules

Following MAJOR modules are available as standard:

Article # Name DPDS modules with digital & analog outputs

3009081 C-MAJOR-4-1212-1.0-A SiC, 1.6 mm²

3009082 C-MAJOR-4-2525-1.0-A SiC 5 mm²

3009083 C-MAJOR-4E-0505-1.0-A SiC, 0.3 mm², erythemartig

3009086 D-MAJOR-17-3000-1.0-A InGaAs Digital Photodiode, 3 mm, 1.7 µm

3009087 D-MAJOR-17-1000-1.0-A InGaAs Digital Photodiode, 1mm, 1.7 µm

3009088 E-MAJOR-22-1000-1.0-A x-InGaAs Digital Photodiode, 1 mm, 2.2 µm

3009089 E-MAJOR-26-1300-1.0-A x-InGaAs Digital Photodiode, 1.3 mm, 2.6 µm

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3. Interfacing MAJOR Modules

3.1 Connector Layout

MAJOR modules are grouped generally into two types: Modules with only digital outputs and modules with simultane-ous digital and analog outputs. This is due to two different interface wiring maps. The signals on the two connectors are mostly the same except the signals on pin #1 and #2 as described in the two following tables. Both types can be connected to a PC directly over the RS232 port or via a RS232-to-USB converter to the USB port of a PC.

MAJOR modules which are marked with a “-A” at the end of their part numbers are the MAJOR modules, which can output sensor data digitally and analog at the same time.

MAJOR-A modules with analog and digital signal outputs

Pin# Signal Name Electrical data Description

1 TempOut 0… 2500 mV Analog temp output

2 SensorOut 0…3300 mV Analog sensor output

3 +5V 5V ±10% Power supply input

4 TxD RS-232 levels Serial data output

5 BSLprg RS-232 levels BSL programming signal

6 RxD RS-232 levels Serial data input

7 Reset RS-232 levels Reset input signal, low active

8 GND 0V Ground signal

MAJOR-A modules are the candidates to output either two analog values on their pins 1 and 2, or to be customized to use one pin as a trigger input and one pin as a trigger output for customized applications, where a triggering signal is needed for their integration into other systems.


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MAJOR modules with two digital interfaces and no analog outputs

MAJOR modules, which have a second RS-232 interface instead of the analog signal pins can be interconnected to each other. Thus, a chain of detectors can be made which are capable of communicating with each other without the need of any host(s) in between:

Pin# Signal Name Electrical Data Description

1 TxD1 RS-232 levels Serial data output 1

2 RxD1 RS-232 levels Serial data input 1

3 +5 V 5 V ±10% Power supply input

4 TxD0 RS-232 levels Serial data output 0

5 BSLprg RS-232 levels BSL programming signal

6 RxD0 RS-232 levels Serial data input 0

7 Reset RS-232 levels Reset input signal, low active

8 GND 0V Ground signal

3.2 MAJOR – to – RS232

MAJOR module directly connected to a PC / Host using the MAJOR – to BSLcomLink / Serial Cable:

Pin# MAJOR-Signal Description PC-Signal Pin#

4 TxD (out) MAJOR data transmit line to host / PC RxD (in) 2

6 RxD (in) MAJOR data receive line from host / PC TxD (out) 3

8 GND Ground GND 5


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When the MAJOR module is connected to the PC’s RS232 port directly, additionally an external stabilized power supply must provide +5V power to the MAJOR module over the pins shown in the table below:

Pin# MAJOR-Signal Description

3 +5 V Positive pol of the external stabilized power

8 GND Negative pin of the external stabilized power supply

This cable is not included in the scope of supply but can be ordered separately. Standard length is 2 m.

3.3 MAJOR – to – USB

MAJOR module can be connected to a PC over the BSLcomLink adapter and the MAJOR – to BSLcomLink / Serial Cable. This Adapter is not only a RS232-to-USB converter, but also provides the MAJOR module with needed power sourced by USB host. The firmware of the MAJOR module can also be updated via this adapter using the boot-strap- loader software called “ComLink”.

Pin# MAJOR-Module Description BSL-DB9 Pin#

3 +5V (in) +5V power from USB host Vbus 1

4 TxD (out) MAJOR data transmit line to host RxD (in) 2

5 BSLprg (in) boot-strap-loader signal nRTS (out) 7

6 RxD (in) MAJOR data receive from host TxD (out) 3

7 Reset (in) Module reset signal from host nDTR (out) 4

8 GND Ground GND 5

This adapter is not included in the scope of supply, but can be ordered separately.


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3.4 MAJOR – to – MAJOR Interconnection (coming soon)

Pins 1 & 2 are replaced with a secondary RS232 signal pair (TST=BSLprg and RST=Reset) in the “network” version of the MAJOR. Those MAJOR modules can be chained together via the serial port as shown below:


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4. MAJOR Module Commands

The software of the MAJOR module contains beside the AMOS operating system several applications and services to fulfill sensing and processing demands. From user’s point of view following major aspects are categorized into com-mands to configure individually a MAJOR module: sdds : Sensor Digital Data Streaming to a Host / PC over the RS-232 afe : Configuring the Analog Front End of a module individually sup : Storing User Profile into the MAJOR reset: Resetting the module

The MAJOR-A can be configured and monitored by the ComLink software. Alternatively, a terminal program like PuTTY can be used. for monitoring and configuring purposes. For this the MAJOR should be connected to an avail-able serial port of the PC (see Interfacing MAJOR modules for more details). The terminal program should then be able to communicate with the MAJOR using the selected serial port number with following configuration:

115200 baud, 1 stop bit, no parity and no flow control

The MAJOR contains a command processor, which allows the user to interact with the module over the termi-nal program. Any character typed by user into the terminal program is echoed back by the MAJOR followed by command’s output.

4.1 The SDDS Command (Sensor Digital Data Stream)

Syntax: sdds -n -gG -sS -vV -tT -pPPPP -mMMMM -cCCC

This is the main command to a MAJOR module to receive sensor data. The parameters of this command can be grouped into two categories: One group is responsible for WHAT to send and the second group deals with aspects of HOW to send the sensor data to the host. There is no need to send the command with all its parameters or in a fixed order to the MAJOR. Missing parameters will be handled with default values.

When a MAJOR module is connected to a PC and the user types the command “sdds” without any parameters, then the MAJOR module provides the user with a brief help information how to use the command:


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The parameters dealing with WHAT to send are:

Node-ID Since modules can be cascaded on one digital line, a node ID is needed to separate received sensor values of different modules. Parameter syntax: -n Default value: No print of the node ID The node ID at start of a record of a data line shows to whom a specific sensor value is belonging. If the switch is used with the command, then the node ID will get also printed in the terminal program.

Examples:

Graphical curve Sensor samples can be displayed as a semi-graph-ical-curve within the text window of the terminal application using normal text characters. Parameter syntax: -gG G in the syntax stands for a single digit: 0 = disabled 1 = enabled Default value is 0 This function is only to give a simple imagination of received sensor values when using normal hyper terminal applications like PuTTY. In normal cases it is recommended to use the more featured “ComLink” software as a tool for monitoring sensor values. When using this parameter to show sensor values graphically, then it is recommended not to output many other values like time stamp or temperature, when fast data changes occur. Due to limited serial link bandwidth of 115200 baud, fast changing sen-sor values would result into “chopped” curve display due to overflow of the internal sending buffer.

Examples:


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Timestamp Any taken sample by MAJOR module has an internal time stamp. The time stamp can be shown in three different formats when sending the data to the termi-nal. Parameter syntax: -sS S in the syntax stands for a single digit value in the range of 0 to 2: 0 = milliseconds 1 = hour:min:sec 2 = days – hour:min:sec Default value is 1 After reset a timer starts to run keeping running time of the module. This value is used for time stamping of the measurement data. Since the module doesn’t have a backup battery inside, the time starts at zero every time the module is powered up or gets a reset event. When the module is connected to a host and one time stamp is linked to a real clock time, all other timestamps will also get a fixed relation to an actual clock time. In standard application the smallest clock step be-tween to timestamps in a MAJOR module is 10 ms, which means time stamping for signal frequencies up to 100 Hz. For long term measurements a day counter keeps the number of the days in front of the normal hour-min-sec value.

Examples:


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Value Measurement data can be displayed in three differ-ent formats when they are sent to the terminal. Parameter syntax: -vV V in the syntax stands for a single digit value in the range of 0 to 2: 0 = millivolts 1 = ADC raw data as a Hex value 2 = both formats are displayed Default value is 0 The total ADC input range is 2500 mV, which is con-verted to a 12-bit value. As a result we would have a maximum of 3 Hex digits starting from 0x000 to 0xFFF corresponding to the 2500 mV input rage. Each LSB corresponds to approx. 610 µV. The resulting sensor sensitivity per converter least significant bit would be 610 µV/gain , where gain can be set between 1 and 128. This means the smallest change of voltage value, which can be observed by the ADC is below 5 µV

Examples:


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Temperature Together with any taken sensor sample the tempera-ture at the sampling time can also be recorded. Parameter syntax: -tT T in the syntax stands for a single digit value in the range of 0 to 2 0 = temperature in centigrade [°C] 1 = ADC raw data as a HEX value 2 = both formats are displayed Default value is 0 The µController contains a calibrated temperature sensor on chip, which can be read by the ADC giving back to the user the µController’s temperature itself. Since the electronic and the sensor are very close to each other (sitting within the same M12 screw housing), the temperature from µController is same or very near to the detector’s temperature.

Examples:


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The parameters dealing with HOW to send are listed below. They can be used in any combination; all together or as pairs in any combination or only one of them:

Periodically The MAJOR can be configured to take a sample of the sensor in fixed time intervals. Parameter syntax: -pPPPP PPPP in the syntax stands for a four digit decimal value in the range of 0 to 9999. The value defines the periodi-cal time intervals in milliseconds for taking sample data. For example -p2500 means to take a sample each 2.5 seconds.

Monitoring The ADC has 12-bit resolution. In decimal it means, the ADC would deliver a value between 0 and 4095. Trans-lated in Hex this means a value between 000h and FFFh. The user can tell the MAJOR to monitor the delta Hex change of the sensor value relative to last processed value. This is defined in MAJOR system as monitoring. Parameter syntax: -mMMMM MMMM in the syntax stands for a four digit Hex value in the range of 0010h and 0FFFh.

For example if -m0020 is used, then the MAJOR will print out a sensor data record if the sensor value changes more than 20h relative to the last printed sample value. Then the MAJOR continues to monitor relative to this new printed value, if the difference gets more than 20h, and so on.

Counter This switch limits the sending of data records to a host to a defined number. When a period and/or monitoring is defined, additionally the user is able to tell the MAJOR to stop sending data after a defined number of records. Parameter syntax: -cCCC CCC in the syntax stands for a three digit decimal value in the range of 001 and 999. Default value is 10 For example if -c100 is given in the command, the MAJOR stops sending sampled data after sending 100 records to the host.


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4.2 The AFE command (Analog Front End)

Syntax: afe -gG -oOOO -agcS -gmM -aAA -rR

The MAJOR hardware allows the software to apply offset voltages or gains to received signals from the detector on its way to the ADC converter. Following schematics shows this in detail for a better understanding of the AFE com-mand and its parameters.

When a module is connected to a PC and the user types the command “afe” without any parameters, then the MA-JOR module provides the user with a brief help information how to use the command. The picture below shows this screen shot:


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When using the ”afe” command, the user can set following parameters before detector signal reaches the ADC:

Gain Eight different fixed gains can be applied to the detector signal. Parameter syntax: -gG G in the syntax stands for a single digit value in the range of G=0, 1, 2, 3, 4, 5, 6, 7. This would result in the gains = 1, 2, 4, 8, 16, 32, 64, 128 Default value is 3 means a gain of 8

Offset An offset threshold to detector’s signal level results to eliminate unwanted DC and noise signals. The implemented differential amplifier amplifies only positive levels relative to the configured threshold level. Noise and unwanted signal levels below this threshold are not seen by the ADC using this technique. Parameter syntax: -oOOO OOO in the syntax stands for a up to 3 digit decimal value between 0 and 256 Default value is set to 0 Each step means 5034 µV of offset voltage to detector signal level

Automatic Gain Control The gain for the detector signal can be changed automatically based on last taken sample. An example of auto-matic gain control and its dynamics is given in the following graph:


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The gain increases one step if signal level falls below 30% of ADC’s dynamic range, or decreases one step if the detector signal level rises over 90% of ADC’s dynamic range.

Parameter syntax: -agcS

S in the syntax stands for a single digit value in the range of 0 to 1. Zero means automatic gain is turned off and one means it is active.

Default value is 0

The automatic gain control is traceable, i.e. at setting “agc1” the referring single digit value per gain syntax is auto-matically printed in front of sensor reading.

Max-Gain (for auto-gain option) When auto-gain option is activated and no detector signal is present, the auto gain would apply the maximum gain of 128 to the detector signal. This maximum can be reduced to the value given by this parameter. Parameter syntax: -gmM M in the syntax stand for a single decimal digit in range of M = 0, 1, 2, 3, 4, 5, 6, 7. This would result in max-auto-gains of 1, 2, 4, 8, 16, 32, 64, 128. Default value is 7 When the detector signal is conditioned as explained above, the MAJOR itself allows various configuration possi-bilities. Most of them are application based and handled internally. following configurations were made available to the user in actual firmware:

Averaging Each sample value delivered to the higher level software by the MAJOR module can be averaged over 2, 4, 8 or 16 taken samples. Parameter syntax: -aAA AA in the syntax stands for 1, 2, 4, 8 or 16 Default value is 4, which means that any value presented to the system is an average of 4 taken samples within approx. 20 microseconds. Setting to 1 means no averaging.

Vref- The ADC converts a value against a reference value, normally against the ground level, but it can also convert the signal against a level other than ground. The MAJOR can be configured to convert a signal against the offset value configured in the section above. Parameter syntax: -rR R in the syntax can be either 0 or 1. With 0 the Vref- will be set to internal ground of ADC and if set to 1, then the Vref- of the ADC will be the configured offset value described earlier (see “Offset”). Default value is 0, means the reference is the internal ground of the ADC.


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4.3 The RESET command

Syntax: reset

With this command a warm reset will apply to the MAJOR. Following (or similar) information will be displayed in the hyper terminal window after a reset:


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4.4 The SUP command

Syntax: sup

This command will save the actual configuration of the MAJOR module into the flash memory. After a power cycle or after a reset the module will exactly continue to work as in the moment of executing this command.


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5. Electronics

5.1 Introduction

The MAJOR is based on the ACU2 module. This mod-ule is a very small hardware with a powerful firmware, ready to be integrated into many applications. It contains the latest Programmable-Digital-Sensor software, which runs on top of the real-time operating system AMOS. An analog sensor can be connected to this board to provide a host / PC with sensor data in digital form over the RS-232 link, together with time- & temperature- stamps. Any sensor signal conditioning and calibrations are handled by the ACU2 module as per individual stored configura-tions within the module.

5.2 DescriptionThe Controlling Unit – Type 2 (ACU2) is designed to be an interface for various sensor types. It is capable of storing sensor data locally using an onboard serial Flash with 4 MByte of capacity. Together with each record, the ACU2 can also store a time stamp and the temperature of the sensor at recording time.

The form factor is kept so small, that it can be integrated together with the sensor itself into a very small housing. The PCB is optimized to be fitted into M12 screw housing which is commonly used in industry.

ACU2 can output sensor data and temperature data in analog and digital form on its interface. The digital interface of ACU2 is based on RS232 technology and can transmit the serial data about 15 meters on a cable. The baud rate is user selectable and up to 115200 baud.

A number of ACU2 modules can be networked together using one cable. It can be connected in parallel or cascade mode to build a chain. Each module in the chain gets its own address (automatically or manually). Individual com-munication with each module is based on the module address inside of the chain.

Digital processing and interfacing of the module is based on a 16-bit RISC processor with 16 MIPS, 128kByte Flash and 10 kByte SRAM. The ADC module is a 200 ksps fast 12-bit SAR analog-to-digital convertor with reference gen-era- tor for sensor biasing if needed.

The chained system can also operate without a host or gateway. The modules are intelligent enough to be grouped and communicate with each other without the need of a master or host module. Configuration and data exchange with ACU2 can be done directly over a RS232 serial port on PC using a hyper terminal application.


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Basic schematic

5.3 Features General

16-bit mixed signal RISC microcontroller with 16 MIPS 128kByte code Flash, 10 Kbyte SRAM and additional 4MByte external serial Flash 12-bit 200ksps Analog-to-Digital converter with Reference voltage and auto scan Basic timers with real-time clock feature and time stamp for logging purposes SPI controlled programmable gain amplifier with input multiplexer Analog sensor and temperature voltage output with 200 mA driving capability Local long term logging capability for 500.000 records with time & temperature stamps

Sensor Input Interface Low Noise: 12 nV/√Hz Offset: 25 µV, 100 µV (max) Zerø Drift: 0.35 µV/°C, 1.2 µV/°C (max) Two Channel MUX Gain Error: 0.3% max Gain Switching Time: 200 ns Input Offset Current: ±5 nA max (+25°C) Binary Gains: 1, 2, 4, 8, 16, 32, 64, 128 Gain Bandwidth: 350 kHz @ G=128 to 10 MHz @ G=1 Calibration channels @ 10% and 90% Configurable signal reference voltage Operating temperature range -40°C to 125°C


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Digital Interface RS-232 transceiver with three-driver and five-receivers Specified for data rates up to 1000-kbps Enhanced ESD interface Protection: ±8 kV IEC 61000-4-2 Air-Gap Discharge ±8 kV IEC 61000-4-2 Contact Discharge ±15 kV Human-Body Model

5.4 Wiring exampleAn interesting aspect is how to wire the sensors to each other to create a networked system with same or different sensor types in the chain. Beside other alternative wiring scheme, one possible scheme is the cascaded wiring of the sensors shown in the figure below.

In this topology the modules are able to number themselves automatically. Each module has its own address to distin-guish communication between the modules. If modules are added or removed, the chain is able to detect the change automatically and initiates a re-addressing of the modules in the chain.

This chain can operate without the need of a host system. Any module in the chain is able to communicate with another individual module if desired. The number of sensors in the chain is not limited, but it is recommended to not exceed 256 sensors in a chain.

Both ends of the chain may be connected to each other as shown to realize a ring topology. Data shifted to the ring may be verified by sender if an application requires double checking of transferred data through the chain.

5.5 Local long term logging capability

The ACU2 is able to log sensor data together with a time and temperature stamp per record. More than 500.000 records can be stored in ACU2. If each minute one record is stored, the ACU2 can store more than one year of data locally!

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5.6 Electrical Interface


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Pin Listing

Pin# Pin-Name Type Descriptions

1 +5 V Power Main Supply voltage

2 SensorTemp Analog Out Firmware controlled output voltage Digital to Analog converter with 256 steps with Vref+ selectable by software (1.5 V, 2.0 V or 2.5 V)

3 GND Power Ground

4 Reset RS232-In Software controlled (enable /disable) µController-Rest pin

5 TxD0 RS232-Out UART0 serial data output

6 BSLprg RS232-In Trigger signal for entering BSL mode programming of the µController in conjunction with Reset pin #4

7 RxD0 RS232-In UART0 serial data input

8 RxD1 RS232-In UART1 serial data input

9 SensorOut Analog Out Analog Sensor Conditioned output voltage

10 TxD1 RS232-Out UART1 serial data output

11 TDO GPIO JTAG ping in programming and Debugging mode General purpose digital I/O pin as alternative function

12 TDI GPIO JTAG ping in programming and Debugging mode General purpose digital I/O pin as alternative function

13 TMS GPIO JTAG ping in programming and Debugging mode General purpose digital I/O pin as alternative function

14 TCK GPIO JTAG ping in programming and Debugging mode General purpose digital I/O pin as alternative function

15 RST Output Reset signal to connected peripherals

16 Sensor In+ Analog-In Positive analog sensor input signal

17 Sensor In- Analog-In Negative analog sensor input signal


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6. The Operating System

6.1 Introduction

An embedded real time operating system called AMOS (ANSARI’s Micro Operating System) has been developed in order to answer complex demands in small networked modules. The modules operate with low power 16-bit µControllers.

AMOS is a multitasking real-time operating system with optimized communication capabilities within its kernel. It sup-ports up to 16 different communication channels and up to 96 user and system tasks to operate simultaneously and needs a very small footprint for its operation (less than 50 kByte of system code and only 2 kByte of SRAM!). The rest of the Flash and RAM areas can be used by user applications.

The MAJOR software is based on AMOS. This software ensures long term compatibility and has been developed based on experiences of several previous projects. AMOS is based on following rules:

Optimized usage of system resources Independent OS and application structure Self-sufficient Communication capabilities Integrated remote and multitasking capabilities Table and pointer organized data and function structure Memory and storage reorganization at runtime and not only at compilation time

6.2 Sections

AMOS contains various sections. Following is a brief introduction to those sections, which are used in MAJOR modules:

The Scheduler The heart of AMOS is a special task scheduler, which is not based on time slice distribution between tasks like many other operating systems. AMOS allows a task to run as long as needed and supports highly any real time oriented application. On the other hand AMOS is more interrupt driven rather than polling driven. The kernel has the ability of setting different priority levels to tasks within runtime.


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Memory Management A powerful implementation in AMOS is the software controlled memory management. The whole physical avail-able memory is declared as a shared memory for the whole system and portions are allocated and released freely as needed by the kernel, communication buffers, system tasks or user applications. Also the main system stack and user application stacks are flexible in size while runtime using this shared memory system.

Communication Links A communication management module called ComLink handles packet based communication between running tasks locally and also between any running tasks and external world over available hardware links in the system like UART, SPI, I²C, USB etc. Generally packet types are distinguished as verbose or transparent. Verbose packets for example allow a user to talk with the kernel using normal text commands over a hyper terminal. Inter-Process-Communication (IPC) packet is a transparent packet example, which enables any task to communicate to other internal tasks or external world based on a protocol.

RTC and Timers A timer unit realizes unlimited and independent timers for any tasks in the system, while the timer module itself handles any kernel relevant timing issues including RTC functionalities. An application may request any type of timing values from 80µSec up to hour and days based timings.

Error & Warning Handler System error, warning and status handling facilities operate as intelligent shadow logic beside normal kernel operation to prevent system crashes and keep the kernel alive and operating in fault conditions. Heavy messaging and status reporting capabilities are realized to outside world fully transparent to local tasks for better interopera-tion of multiprocessor systems.

Multilanguage Messaging Integrated multi language messaging system enables tasks and system messages to be sent to the user (e.g. terminal emulators) not only in English, but also in another language. The message language can be changed in run-time from English to other custom language or vice versa.

Type Conversions Complete string and number and variable type conversions are available to any tasks by APIs.

Mathematics Complete Integer (8, 16, 32 and 64 bit), fixed point (16, 32 and 64 bit), and floating point (IEEE 754, 32 and 64 bit) arithmetic functions are available to any application in the system over given APIs


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6.3 AMOS Add-Ons

Add-Ons are standalone library components, which can be added to the firmware at compile time providing extra functionality to the operating system needed by user applications. These functions are available by APIs to the user. Any data transferred between user applications and the add-on modules are based on IPC packets.

The add-on list grows continuously as project demands come up Following is a brief introduction to those sections, which are used in MAJOR modules:

AMOS-ADC Enables the µcontroller integrated analog-to-digital converter capabilities to user application, without having to understand deeply how to configure the ADC peripheral. Several services are provided to an application such as automatic monitoring and message triggering on monito-ring analog signals.

AMOS-DMA Provides the user application with flexible runtime configurable DMA services between different hardware and software modules.

AMOS-GPIO Controls all system GPIOs and allocates functions to pins and tasks at runtime. Provides application based alloca-tion of a pin and shares the hardware resource between applications and secures misusages by applications.

AMOS-CMD A command processor to interpret received verbose commands from user over a hyper terminal to control the sys-tem as needed. Many system applications can be terminated, executed or be requested to send status information by sending verbose commands over the hyper terminal. Also user applications can use this command processor for their applications to be controlled by verbose commands.

AMOS-STG This add-on provides storage capability to the system. The whole unused Flash area on the µController itself and additional external serial Flash storage over SPI is emulated as an EEPROM to user application to save applica-tion data if needed. Larger file handling and logging capabilities can also be realized over this add-on.

AMOS-RTC Any calendar time related events and alerts can be used by user application if this add-on is enabled. Also time stamp capability for logging is supported by this add-on.

AMOS-SPI Any external devices, which may be connected to the µController over the SPI can be accessed in a high level manner using this add-on. It adds read and write APIs to external devices for user applications


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AMOS-I²C Same as SPI add-on but over I²C interface. Additionally a powerful verbose command facility allows the user to access any I²C device in parallel, while the applications are running independently. Detailed information how to use these add-ons are given by existing example codes.

6.4 AMOS Modules

Modules are hardware abstraction layer codes to embed external devices into the system as API based functions. For each external component in the hardware a module code may be created to realize always same functionalities within different projects. This helps to improve the interoperability of the firmware in different products.

6.5 AMOS – ComLink Service

Many hardware modules in the field can be grouped into either sensors or actors. In a decentralized structure, the communication between these modules and their process-levels gets very important. From communication point of view, the communication between modules can be broken down even into the needs between the tasks inside a hardware module. As a result we can imagine a network of sensors and actors with their view of communication needs on one side, followed by the hardware modules itself with their internal process communication needs on the other side.

With this insight, internal and external communication has become one of the core elements of AMOS. A service called ComLink serves any communication and linking needs in an AMOS based environment and handles the two viewpoints seamlessly: The internal communication between tasks inside the hardware and the external communica-tion between different hardware modules.


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Inter – Module Communications

To keep the nature of the communication system as simple as possible we consider networked modules limited only to a simple chain and prohibit mashed configurations. As a result each module needs at least two independent communication channels: one to its “left” or previous and one to its “right” or next neighbor module.

Each chaining element runs the same communication algo-rithm and supports an additional third communication channel for interconnecting two different chains to each other, provid-ing routing and gateway functionality, or giving an interface for servicing aspects.

As shown in figure below, we can now build a chain of modules, where each module acts as a chaining element and sometimes it additionally acts as a gateway or it provides a service interface to a servicing node. The two green and orange chains are interconnected over the green-chain-element #2 and the orange-chain-element #3. The ComLink algorithm in any hardware module is capable of routing data between chains, whenever the “third” channel is used. Module addressing is a system integrated automatic procedure.

The service node can interchange data to any of the hardware modules in both chains, due to routing capabilities of any single chain element. The ComLink logic is built in a way, that each chain element gets dynamically its own address in the network. Each module is capable to communicate with any other hardware module in a point to point manner. When one chain element receives a packet, it analyzes the destination address stored in the packet and routes the packet, if the packet is not desired for the chain element himself.

ComLink is independent of channel’s physical layer. The favorite physical layers are UART (RS-232) and Bluetooth links, but SPI, I2C, CAN and other type of communications are also supported.


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Three simultaneous wireless links to three remote nodes can be established in parallel, when Bluetooth is chosen as physical layer. Two channels build the “left” and “right” links and one channel is basically for human interface con-nection like an iPhone to exchange data with the wireless chain.

A fourth wired channel is also available for linking to wired chains. Routing between different physical layers like wired to wireless and vice versa is fully supported and transparent to applications.

The data transmitted over any channel can be set to transparent (binary data) or verbose (readable strings). When a single module is connected to a PC, a user can use a terminal program like PuTTY to communicate with the hard-ware in verbose mode. AMOS accepts command strings from the user and replies with readable strings to the user. But when more devices are chained together, more complex data needs to be exchanged between the modules. Therefore the communication algorithm switches to transparent (binary) mode and the user needs to use the ANSARI – ComLink, a windows based software tool, to communicate with any of the modules in the chain.

AMOS detects automatically the environment, in which it is installed and switches between verbose and transparent mode automatically. Verbose communication is not protocol based, but transparent mode is protocol oriented and communication is packet based and structured.

A verbose packet starts always with an ASCII printable character. This means the first byte transmitted has a value greater than 31 (or in Hex 0x1F). A verbose command ends always with an ASCII carriage return or a line feed control code.

More data can be found in online forum: http://ansari-electronics.com/comlinksrv/


http://ansari-electronics.com/comlinksrv/

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7. Accessories (not included, can be ordered separately)

7.1 MAJOR – to – BSLcomLink / Serial Cable

This cable adapts the MAJOR module M12 A-coded Sensor connector, series 713 from BINDER with the part number 09-0381-274-08 to the serial port of a PC / Host with a 9 pin Sub-D (or DB9) male connector.

This cable can be used to connect any MAJOR module directly to the serial port of a PC / Host and acts as a Null- Modem cable. Same cable can also be used to connect any MAJOR module over the BSLcomLink Adapter to the USB port of a PC / Host.

The firmware of a MAJOR module can be upgraded / updated using this cable together with the BSLcomLink adapter.

Pin Description

Pin# M12-connector Description DB9-Connector Pin#

1 NC Not connected

2 NC Not connected

3 +5 V (in) +5 V power from USB host Vbus 1

4 TxD (out) M12 data transmit line to DB9 RxD (in) 2

5 BSLprg (in) boot-strap-loader signal nRTS (out) 7

6 RxD (in) M12 data receive from DB9 TxD (out) 3

7 Reset (in) Reset signal from DB9 to M12 nDTR (out) 4

8 GND Ground GND 5

Not connected NC 6

Not connected NC 8

Not connected NC 9


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7.2 BSLcomLink Adapter

The BSLcomLink Adapter realizes 3 functions in one: USB to Serial (RS-232) adapter BSL programmer for ACUx modules (using BSLcomLight

software) Providing ACUx modules with +5 V power (sourced

over USB host device)

Data transfer rates of up to 1 Mbps can be achieved by this adapter between an USB-host and an ACUx module. The used FTDI / FT232RL chip set makes the driver installa-tion easy and guarantees the adapter to be compliant with USB 2.0 standards.

When using this module together with the BSLcomLink software and the MAJOR – to – BSLcomLink / Serial Cable, the firmware of a connected MAJOR module can be updated or upgraded. The adapter has the needed BSL signals integrated to reprogram the firmware using boot-strap-loader algorithm.

At the same time this adapter forwards the Vbus power from the USB interface towards the connected ACUx module providing needed power to the ACUx to work. Due to USB limitations, the maximum current, which can be provided to a number of connected ACUx modules, should not exceed 400 mA.

Driver Installation

The driver will install automatically when you plugin the adapter into your computer. If not, you can download and install the driver per chapter 8.

Pin Description

Pin# Signal Name Description

1 +5 V Power Supply Output: U= +5 V ±10% Imax= 400 mA

2 Rxd RS-232 serial input: Receive line

3 TxD RS-232 serial output: Transmit line

4 Reset RS-232 level output: Reset signal to ACUx

5 GND Power and signal ground

6 NC Not connected

7 BSLprg RS-232 level output: BSLprg signal to ACUx

8 NC Not connected

9 NC Not connected


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8. Update, FAQ and Forum

Due to the nearly unlimited numbers of possibilities with the MAJOR any written documentation will be after a while incomplete, since the technology is moving rapidly forward. Therefore this manual can give the basics only.

The MAJOR modules are built using electronics and firmware developed by ANSARI GmbH, who provide at the same time the latest information and updates related to the electronics and firmware of MAJOR product family.

Below you can find several links to established forum and FAQ services created for MAJOR product series.

Online Information / Literature: MAJOR module overview

Link: http://ansari-electronics.com/major/

Detailed hardware information can be found in the post ACU2 – ANSARI Controlling Unit (Type 2) Link: http://ansari-electronics.com/acu2/

The BSLcomLink Adapter allows to connect the MAJOR via the USB port to a PC Link: http://ansari-electronics.com/bslcomlink/

Some useful interfacing information can be extracted from Interfacing PDS Modules Link: http://ansari-electronics.com/pdsinterface/

The Hardware Quick-Start Guide explains how set up PuTTY for communicating with the MAJOR Link: http://ansari-electronics.com/hwquickstart/

The ComLink Software post explains how to use all given communication features Link: http://ansari-electronics.com/comlink/

The post PDS-Module command gives a detailed overview of how to configure the module via PC Link: http://ansari-electronics.com/pdscmd/

BSLcomLink Driver Installation Package in case the driver will not install automatically Link: http://ansari-electronics.com/bslcomlink/

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http://ansari-electronics.com/

http://ansari-electronics.com/major/

http://ansari-electronics.com/acu2/

http://ansari-electronics.com/bslcomlink/

http://ansari-electronics.com/pdsinterface/

http://ansari-electronics.com/hwquickstart/

http://ansari-electronics.com/comlink/

http://ansari-electronics.com/pdscmd/

http://ansari-electronics.com/bslcomlink/

major: a series of digital photodiode sensors (dpds) 1 ......the major-series of modules are capable...

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