Step – Comtrol Modbus TCP Quick Start User Manual
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DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read/Write Raw/ASCII Devices - 57
Configuring Read/Write Raw/ASCII Devices
h. Enter the PLC IP Address:
•
For Modbus/TCP slaves, set the PLC IP Address to that of your PLC in xxx.xxx.xxx.xxx format.
•
For Modbus/RTU or Modbus/ASCII serial slaves, set the PLC IP Address to that of this
DeviceMaster UP in xxx.xxx.xxx.xxx format.
Note: The Modbus serial slave must be attached to one of the serial ports on this DeviceMaster UP
chassis.
i.
Enter the PLC Device ID:
•
For Modbus/TCP slaves, set the PLC Device ID to that of your PLC. This is typically 1.
•
For Modbus/RTU or Modbus/ASCII serial slaves, set the PLC Device ID to that of the serial slave
device.
Note: This must be a unique device id attached to this DeviceMaster UP chassis.
j.
Set the PLC Tx Data Address to the PLC memory address at which to request the transmit data
message. This is Base 1, which means the address starts at 1 (or 400001 for some PLCs). If your
address range is Base 0, or starts at zero, you will need to add one to your address.
k. 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.
l.
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.
m. 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.
13. 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