Comtrol Modbus TCP User Guide - Manual (Page 50)

50 - Chapter 3. Embedded Configuration Pages DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I
Modbus/TCP Master Rx/Tx Settings
PLC Tx Data Address
Specifies the PLC address to request transmit data messages while operating
in the Master Transmit Transfer mode. The data area must be comprised of 16
bit words and contain a sequence number, length, and data to transmit. An
updated sequence number will indicate new data to transmit. Therefore, the
length and data must be written to the transmit data area before updating the
sequence number.
The address is base 1. Therefore, if your address scheme starts at zero, you will
need to add one to your address.
PLC Tx Poll Rate
Specifies the rate, in milliseconds, that the DeviceMaster UP will poll the PLC
for transmit data. The default is 100ms
PLC TX Poll Message
Length
Specifies the length, in bytes, of the transmit message the DeviceMaster UP
will request from the PLC. This must be large enough to contain the largest
size data packet plus four bytes for the sequence number and length fields. Any
extra bytes received from the PLC will be ignored. The default is 250 bytes
Tx Sequence Number
Syncing Enable
If the Tx (From PLC) Transfer Mode is operating in Master (Poll the PLC); this
specifies whether or not to enable synchronizing transmit data messages
between the PLC and the DeviceMaster UP. This setting is clear by default.
PLC Tx Consumed
Sequence Number
Address
Specifies the PLC memory address at which the DeviceMaster UP will 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.
Modbus/TCP Master Rx/Tx Settings (Continued)