Connecting Modbus RTU master cards SCU

Introduction
This tutorial is intended to explain the connection of Modbus RTU masters cards SCU.
 
The CJ/CS1W-SCU21/41 * cards are capable of gateway-mode command to convert a Modbus FINS command.
I. Configuring SCU map

1. In Cx-Programmer, set port 2 mode User, Gateway, 9600, 8, N, 1:
 

2. Transfer the settings in the map.

 Warning: the value of Serial Gateway Response timout should always be less than the timeout defined in the CMND (C 5) multiplied by the number of tests


II. Programming instruction CMND

@CMND490  
Source Modbus Query preceded FINS command code 2804 (Modbus conversion)
Destination Mailing address for reply
Control Execution parameters of the instruction

 The destination instructions CMND, SEND, RECV are intelligently made using the traditional routing PURPOSES, No network N + No node n + u. No Unit
Since the V3 version of CPU CJ / CS, the recipient unit may be appointed directly from the Unit No. added as an offset. This trick of writing allows you to dispense with a routing table in the PLC.

Without routing table Network Node Unit
SCB (card inserted in the UC) 0 0 Port 1 : E4 Port 2 : E5
SCU (maps) 0 0 Port 1 : 80 + 4x n° Unit
Port 2 : 81 + 4x n° Unit
 

1. Writing Query (0x10) from ABCD in 0002 via the register map SCU21 port 1 Unit No. 0

  Description of the Source block Example
S 2804 -> FINS Code for Modbus conversion 2804
S+1 No. of slave Function code 0110
S+2 Modbus write register address 0002
S+3 Amount of write register 0001
S+4 Qty bytes (S 3) x2 data (MSB) 02AB
S+5 data (low) not used CD00

 

 

  Description of the Destination block Example
D 2804 -> FINS Code for Modbus conversion 2804
D+1 Code to execute the FINS command 0000
D+2 No. of slave Function Code 0110
D+3 Modbus register address 0002
D+4 Amount of Modbus register   0001

 

 

  Description of the Control block Example
C Size of the query S (11 bytes) 000B
C+1 Size of the expected response D (10 bytes) 000A
C+2 Recipient network. The FINS command 0000
C+3 Destination node Unit destination 0080
C+4 Response Logical port Number of tests 0000
C+5 Response time 2s 1 = 0000 to FFFF (0.1 to 6553.5 s) 0000

2. Reading Query (0x03) of words to address 01FF via map SCU21 port 2 Unit No. 2 

  Description of Source block Example
S 2804 -> FINS Code for Modbus conversion 2804
S+1 No. of slave Function Code 0103
S+2 Modbus read register address 01FF
S+3 Amount of read register 0002

 

 

  Description of Destination block Example
D 2804 -> FINS Code command 2804
D+1 Code to execute the FINS command 0000
D+2 No. of slave Function code 0103
D+3 Quantity of bytes Data (MSB) 0400
D+4 1st read data (low) 2nd read data (MSB) 0100
D+5 2nd read data (low) Not used 0200

 

 

  Description of Control block Example
C Size of the query S (8 bytes) 0008
C+1 Size of the expected response D (11 bytes) 000B
C+2 Recipient network. The FINS command 0000
C+3 Destination node Unit destination 0089
C+4 Response Logical port Number of test 0000
C+5 Response time 2s 1 = 0000 to FFFF (0.1 to 6553.5 s) 0000

 

Link:
http://www.myomron.com/index.php?action=kb&print=1238


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