Step – Comtrol Modbus TCP Quick Start User Manual
Page 32
32 - Configuring Read-Only Raw/ASCII Devices
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read-Only Raw/ASCII Devices
k. Set the Use Maximum Sized Modbus Messages option if you are receiving messages over 196 bytes, your
PLC can receive messages larger than 200 bytes, and you want to decrease latency and network usage
l.
Go to Step
on Page 32 to complete configuration.
10. Slave Receive Transfer Mode Only:
Use the following procedure to configure the Slave Receive Transfer mode.
Under Serial Modbus Master and Modbus/TCP Settings (Raw-Data Only):
a.
Set Rx (To PLC) Transfer Mode to Slave (PLC Polls).
b.
Set Tx (From PLC) Transfer Mode to either Slave (PLC Writes) or Off.
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 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.)
11. Set up the Filtering/Data Extraction Configuration settings:
•
If no filtering/data extraction is required, leave all filtering/data extraction settings to defaults (off).
•
If filtering/data extraction is required, see