cp400 as modbus rtu slave

8/17/2019 CP400 as Modbus RTU Slave

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001 PROGRAM PLC_PRG

002 VAR

003 END_VAR

004 (*Demo program-CP terminal as slave CP_as_Modbus_RTU_slave.pro - AC500 program

005 CP_slave2.V6F and CP_slave3.V6F - CP440 programs

006

007 Main purpose: how to handle Modbus RTU communication using step chain ( in ST in this example )

008

009 Modbus RTU master : COM1 - PM571

010 Modbus RTU slaves: CP440 - slave2 and CP 440 slave 3

011 RS485, 19200, 8 1, even

012 The CP440 programs are identical, they consist of:013 Screen 1: 3 actual values from the CPU, Screen 2: 2 actual values from the CPU

014 Screen 1: 2 set values to the CPU, Screen 2: 3 set values to the CPU

015 The communication consist of:

016 - writing 5 set values to slave 2 and slave3

017 - reading 5 actual values and the screen number from slave 2 and slave 3

018

019 *)

001

CP_communication

002

done_master

COM_MOD_MAST

RTU_Master

EN

COM

SLAVE

FCT

TIMEOUT

ADDR

NB

DATA

DONE

ERR

ERNO

err_master

erno_master

en_master

1

slave_CP

FCT_CP

1000

ADDR_CP

NB_CP

ADR

DATA_CP


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001 PROGRAM CP_communication

002 VAR

003 END_VAR

001

002 (*-----------S L A V E 2-------------------------------------------------------------------------------------------------*)

003 (*write five words to slave2 = screen 1 and 2, actual values 1,2 3,4,5*)

004

005 (*request*)

006 IF CHAIN=0 AND NOT done_master THEN

007 CHAIN:=100;

008 en_master:=TRUE;

009 slave_CP:=2;010 FCT_CP:=16;

011 ADDR_CP:=0;

012 write_all_screens_data:=write_all_screens_slave2;

013 NB_CP:=5;

014 END_IF

015

016 (*reply*)

017 IF CHAIN=100 AND done_master THEN

018 CHAIN:=200;

019 en_master:=FALSE;

020 END_IF

021

022 (*read six words from slave2 - screen 1 and 2, set values 1,2,3,4,5. In the sixth word is the actual screen number*)

023

024 (*request*)


026 CHAIN:=300;


028 slave_CP:=2;

029 FCT_CP:=4;

030 ADDR_CP:=20;

031 NB_CP:=6;

032 END_IF

033

034 (*reply*)035 IF CHAIN=300 AND done_master THEN

036 CHAIN:=400;

037 read_all_screens_data_slave2:=read_all_screens;


039 END_IF

040

041 (*-----------S L A V E 3-------------------------------------------------------------------------------------------------*)

042 (*write five words to slave3 = screen 1 and 2, actual values 1,2 3,4,5*)

043

044 (*request*)


046 CHAIN:=500;047 en_master:=TRUE;

048 slave_CP:=3;

049 FCT_CP:=16;

050 ADDR_CP:=10;

051 write_all_screens_data:=write_all_screens_slave3;

052 NB_CP:=5;

053 END_IF

054

055 (*reply*)


057 CHAIN:=600;


059 END_IF

060

061 (*read six words from slave3 - screens 1 and 2, set values 1,2,3,4,5. In the sixth word is the actual screen number*)

062

063 (*request*)


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065 CHAIN:=700;


067 slave_CP:=3;

068 FCT_CP:=4;

069 ADDR_CP:=30;

070 NB_CP:=6;

071 END_IF

072

073 (*reply*)


075 CHAIN:=0;076 read_all_screens_data_slave3:=read_all_screens;


078 END_IF

079

080 (*communication error*)

081 IF err_master THEN

082 error_CP:=erno_master;

083 END_IF

084


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001 VAR_GLOBAL

002

003 RTU_Master: COM_MOD_MAST;

004 done_master: BOOL;

005 err_master: BOOL;

006 erno_master: WORD;

007 en_master: BOOL;

008 slave_CP: BYTE;

009 FCT_CP: BYTE;

010 ADDR_CP: BYTE;

011 NB_CP: WORD;

012 DATA_CP AT %MW0.100: WORD;013 error_CP: WORD;

014 CHAIN: WORD;

015

016 read_all_screens AT %MW0.100: ARRAY [1..6] OF WORD;

017 write_all_screens_data AT %MW0.100: ARRAY [1..5] OF WORD;

018

019 write_all_screens_slave2: ARRAY [1..5] OF WORD := 0,1,2,3,4;

020 read_all_screens_data_slave2: ARRAY [1..6] OF WORD;

021 write_all_screens_slave3: ARRAY [1..5] OF WORD := 10,11,12,13,14;

022 read_all_screens_data_slave3: ARRAY [1..6] OF WORD;

023

024

025 END_VAR


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CP as Modbus RTU slave

W0

0

actual value1

W1

1

actual value 2

W1

1

actual value 2

W2

2

actual value 3

W2

2

actual value 3

W3

3

actual value 4

W3

3

actual value 4

W 4

4

actual value 5

W 4

4

actual value 5

W20

0

set value1

W21

0

set value2

W22

0

set value3

W23

0

set value4

W24

0

set value5

Screen 1 –S lave 2

Screen 2 – Slave 2 W25 = status block

W5 = control block

W10

0

actual value1

W11

0

actual value 2

W11

0

actual value 2

W12

0

actual value 3

W12

0

actual value 3

W13

0

actual value 4

W13

0

actual value 4

W14

0

actual value 5

W14

0

actual value 5

W30

10

set value1

W31

11

set value2

W32

12

set value3

W33

13

set value4

W34

14

set value5

Screen 1 –S lave 3

Screen 2 – Slave 3 W35 = status block

W15 = control block

CP440 - SLAVE 2

CP440 - SLAVE 3

AC500 CPU as Modbus RTU master with two CP440 as Modbus RTU slaves


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AC500 CPU

Modbus RTU Master

COM 1

1

2

3

4

1

6

CP440 – slave 2

1

6

CP440 – slave 3

RS 485, 19200, 8, 1 even

request

reply

cp400 as modbus rtu slave

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