Step – Comtrol Modbus TCP Quick Start User Manual
Page 40
40 - Configuring Read/Write Raw/ASCII Devices
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read/Write Raw/ASCII Devices
•
Dual Master – Write mode. You can use Dual Master - Write method only if your PLC can operate as
a Modbus master and slave simultaneously. Go to Step
on Page 43 for configuration procedures.
•
Dual Master – Read mode. You can use Dual Master - Read method only if your PLC can operate as
a Modbus master and slave simultaneously. Go to Step
on Page 44 for configuration procedures.
10. PLC Master/DeviceMaster UP Slave Mode Only:
Use the following procedure to configure PLC Master/DeviceMaster UP Slave mode.
a.
Set Rx (To PLC) Transfer Mode to Slave (PLC Polls).
b.
Set Tx (From PLC) Transfer Mode to Slave (PLC Writes).
c.
Set the Maximum Rx Data Packet Size to that of the largest expected receive data packet. This can be a
maximum of 246 bytes in Slave Rx Mode.
d.
Set the Oversized Rx Packet Handling to either Truncate or Drop, depending how you want to handle
oversized received packets.
e.
Set Rx MS Byte First if you want to receive data most significant byte first.
f.
Set Tx MS Byte First if you want to transmit data most significant byte first.
g.
Set the Disable Non-Filtered To PLC Rx Queue option if you only want to receive the last received data
packet. (If two or more packets are received between received data requests, only the last received
data packet will be returned.)