Comtrol Modbus TCP User Guide - Manual (Page 49)

DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I Chapter 3. Embedded Configuration Pages- 49
Modbus/TCP Master Rx/Tx Settings
3.6.2. Modbus/TCP Master Rx/Tx Settings
Use this area to set up Modbus/TCP master receive and transmit settings.
Note: (Raw-Data Only) displays on the serial version of the Modbus/TCP Master Rx/Tx Settings area.
Modbus/TCP Master Rx/Tx Settings
PLC IP Address
Specifies the PLC IP Address of the PLC for operating in either Receive or
Transmit Master mode.
PLC Device ID
Specifies the PLC Device ID of the PLC for operating in either Receive or
Transmit Master mode. The default is 1.
Master Tx Mode Only
PLC Rx Data Address
Specifies the PLC address to write the received data at while operating in the
Master Receive Transfer mode. The data area must be comprised of 16 bit words
and large enough to contain the largest possible received message plus two 16
bit words for the sequence and length parameters.
The address is base 1. Therefore, if your address scheme starts at zero, you will
need to add one to your address.
Maximum PLC Update
Rate
The maximum rate (or minimum time interval) in milliseconds that messages
are sent to the PLC in the Master Receive Transfer mode. This setting
configures the DeviceMaster UP to space the messages to the PLC in order to
prevent overrunning of data before the PLC can process it.
Use Maximum Sized
Modbus Messages
Controls the size of Modbus/TCP messages used to write to the Modbus/TCP
slave device.
• If selected, maximum sized Modbus messages of 242 bytes per message.
• If not selected, Modbus messages of no more than 200 bytes will be used.
The default is Not selected.
Note: This option only takes affect when large messages are received. Selecting
this option may decrease the number of messages sent to the Modbus/
TCP slave, thereby reducing network traffic and latency. However, not all
Modbus/TCP slaves support maximum sized Modbus messages. So, this
setting must be tested with the Modbus/TCP slave to ensure operability