Comtrol Modbus TCP Quick Start User Manual
Page 54
54 - Configuring Read/Write Raw/ASCII Devices
DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read/Write Raw/ASCII Devices
n. Set the PLC Tx Poll Rate to the rate at which you would like the DeviceMaster UP to poll for transmit
messages. If Tx Sequence Number Syncing is disabled, this rate must be faster than the rate at which
you wish to transmit data. If not, transmit messages will be lost.
o.
Set the PLC Tx Poll Message Length to the length in bytes of your longest transmit data packet plus
four bytes for the sequence number and length parameters at the start of the transmit message
(maximum of 250 bytes). Any additional bytes requested will be left unused.
p.
If you wish to enable synchronization of the transmit data messages between the PLC and the
DeviceMaster UP:
•
Enable Tx Sequence Number Syncing Enable.
•
Set the PLC Tx Consumed Sequence Address to the PLC memory address at which you wish the
DeviceMaster UP to write the transmit consumed sequence number. This memory address must
point to a 16-bit word and, like the other address definitions, is base 1. When the Tx Produced
Sequence Number (at the PLC Tx Data Address) and this consumed sequence number are equal, the
DeviceMaster UP has transmitted the last message and is ready for the next transmit message.
Note: Go to Step
on Page 57 to complete configuration.