Goals and Symptoms

This resolution provides a solution for setting serial communication between a Magelis HMISTU655 and a Twido. The RS485 port 1 and port 2 will be used on the Twido to communicate to a HMISTU655 HMI.

Causes and Fixes

Hardware:
TWDLCDA24DRF : Twido Compact PLC
TWDNAC485D: RS 485 connection module for Compact base
HMISTU655: Magelis HMI 3.5"

XBTZ9780 cable: Serial communication cable:
(or XBTZ978 + XBTZN999 adapter)

Software:
Twidosoft v3.5
Vijeo Designer v5.1

1) Setup the Twido Port 1 with the following parameters:
Type: Modbus
Address: 1
Baudrate: 19200
Data Bits: 8 (RTU)
Parity: None
Stop Bits: 1
Response Timeout: 10
Inter-frame delay: 10



Note: Parity must be set to None on Port 1.

2) Configure the TWDNAC485 optional port.

3) Setup the Twido Port 2 TWDNAC485 with the following parameters:
Type: Modbus
Address: 1
Baudrate: 19200
Data Bits: 8 (RTU)
Parity: None
Stop Bits: 1
Response Timeout: 10
Inter-frame delay: 10



Note: Parity can be set to None or Even on Port 2 using the TWDNAC485D.

4) Create the following Ladder section.



This initialize the memory words so that the TWIDO can communication to the HMISTU655. In a real application this may not be required.

5) In Vijeo Designer, configure the Modbus RTU serial driver with the following parameters:

Serial Interface: RS485
Transmission Speed: 19200
Retry Count: 2
Parity Bit: None
Stop Bit: 1
Rcv. Time Out: 1 (Sec)
TX Wait Time: 10 (Msec)

6) In Vijeo Designer, configure the Modbus EQUIPMENT with the following parameters:

Slave EQUIPMENT Address: 1
Preferred Frame Length: Custom, 120 bytes
IEC61131: 0-based
Word Order: High Word First
ASCII Display: Low byte first

7) Create a Integer variable link to %MW10 in Vijeo Designer

8) Add a Numeric Display field and configure as shown below: