Comtrol Modbus TCP Quick Start - Manual (Page 38)

38 - Configuring Read/Write Raw/ASCII Devices DeviceMaster UP Modbus/TCP Quick Start: 2000477 Rev. G
Configuring Read/Write Raw/ASCII Devices
5. Set up the Serial Configuration for your device.
6. Select the Modbus/TCP communication method and set up the Modbus/TCP Interface settings under
General Protocol Settings:
a. Set Serial Port Protocol to Raw-Data.
b. Enable Discard Rx Packets With Errors.
7. Set the Raw-Data Message Transfer mode:
• Selecting Data-Stream enables asynchronous communication to the device.
- Transmit data is sent immediately from all Modbus and active Application interfaces.
- Received data will be returned to the Modbus interface and all active Application interfaces.
- If Data-Stream is selected, the rest of the options in this section are not applicable.
• Selecting Command/Response enables synchronous communications with the device.
- Transmit data will expect one or more responses.
- Responses will only be returned to the transmit message originator.
If Command/Response is selected:
- Set the Response Timeout to a valid timeout period for your device.
- The Cmd/Resp Age Time will set the time at which old responses to the Modbus interface are
discarded.
- The Cmd/Resp Expected Responses Per Command indicates the number of responses expected per
transmitted message. This is typically 1.
- Set the Cmd/Resp Mode Response To Modbus/TCP Based On option to:
- IP-Address if there is only one Modbus/TCP interface per IP-Address communicating to this
port. This is typically used for PLC or single OPC Server/SCADA systems.
- TCP-Connection if there is more than one Modbus/TCP interface per IP-Address
communicating to this port. This typically is required for multiple OPC Server/ SCADA
systems running on the same computer.