October 13, 2009 Mark Kozlovsky 1

Final Production Revision

DECam Heater Controller System

October 13, 2009 Mark Kozlovsky 2

Final Production Revision 1. HEATER DRIVER BOARD

a) Control signals for overheating LEDs were reversed so LEDs were ON all the time. Correction Action: inverters are added in front of opto-couplers.

b) LED power switch which allows for disconnecting LEDs during normal operation had wrong footprint and could not be installed. Correction Action: library part and footprint for the switch were corrected.

c) A screw that holds telemetry connector was very close to +15V_Heater via and sometimes top layer will wear away causing a short. Correction Action: PCB layout is changed to prevent the occurance.

d) Shutdown signals for hot swap controllers were impossible to use and monitor because of crate construction limitations. Correction Action: Signals were brought from transition boards to the Heater Driver Boards to be transferred through additional isolation buffers to the telemetry connectors and further to a Slow Control Subsystem

October 13, 2009 Mark Kozlovsky 3

Final Production Revision

Pin Connection

1 Input Test1

2 Out Test 1+

3 Out Test 1-

4 Input Test 2

5 Out Test 2+

6 Out Test 2-

7 GND_Control

8 GND_Control

9 Overheat 1+

10 Overheat 1-

11 Overheat 2+

12 Overheat 2-

13 nShutDown

14 Aux_Test

15 GND_Control

Telemetry Connector

October 13, 2009 Mark Kozlovsky 4

Final Production Revision

2. HEATER DRIVER BOARD TRANSITION BOARD

a) Value of the resistor R42 was a little bit too small to drive nShutdown signal to log “0” (< 0.8V). Correction Action: Value of Resistor R42 is changed from 3.74K to 4.32K

b) The Hot Swap Controller will sometimes shut itself down because of the inrush current on its negative supply. The setting for the controller shutdown is 4.17A. Correction Action: Value of capacitor BP1 is changed from 0.01uF to 0.047uF in order to limit slew rate for the negative output.

c) Input connector Adam Tech Fully Shielded Mini DIN 8-position Jack had wrong footprint and could not be installed. Correction Action: library part and footprint for the connector were corrected.

d) nShutdown signal was not connected to the Slow Controller Board due to crate construction limitations. Correction Action: nShutdown signal is connected to +5V on J9 in order to be monitored as regular power supply via Analog Power Backplane.

October 13, 2009 Mark Kozlovsky 5

Final Production Revision

3. HEATER PATCH PANEL BOARD

a) The front panel has to be machined around Control input and Heater output connectors to allow plug-in cables to be fully connected. Correction Action: Front panel drawing is changed accordingly

b) The Control input connector has wrong pin assignments on the main schematic. Correction Action: Pin assignments are change according to the Table 1.

October 13, 2009 Mark Kozlovsky 6

Final Production Revision

Pin Number

Incorrect Signal Name

Correct Signal Name

A2 Control_input_12 Control_input_2

A3 Control_input_11 Control_input_1

A5 Control_input_8 Control_input_3

A6 Control_input_7 Control_input_4

A8 Control_input_4 Control_input_5

A9 Control_input_3 Control_input_6

A11 Control_input_2 Control_input_7

A12 Control_input_1 Control_input_8

A16 Control_input_10 Control_input_9

A17 Control_input_9 Control_input_10

A19 Control_input_6 Control_input_11

A20 Control_input_5 Control_input_12

Table 1.

October 13, 2009 Mark Kozlovsky 7

Filter Frequency Response

4. HEATER PATCH PANEL TRANSITION BOARDa) Input connector Adam Tech Fully Shielded Mini DIN 8-position Jack, had

wrong footprint. Correction Action: library part and footprint for the connector were corrected.