Modbus Multi-Station RTU to TCP Converter
4 min
review the following information for setting up and configuring the modbus multi station rtu to tcp converter driver overview the litmus edge modbus multi station rtu to tcp converter driver opens a modbus tcp server listens for requests from clients translates those requests into rtu requests on a multi drop rs485 network repackages the rtu replies as tcp replies use this driver instead of the modbus rtu advanced driver when you want to reuse identical tag names across different station ids to do so, create multiple instances of the modbus tcp driver and add tags to those driver instances you cannot directly add tags to this driver litmus edge compatible series compatibility parameter compatible items driver type rtu client and tcp server validated devices/series modbus rtu stations litmus edge modbus tcp driver replaces gen 1 driver(s) n/a to set up and configure this device in litmus edge, you will need to do the following step 1 set up and configure the plc device step 2 set up the plc device in litmus edge devicehub step 3 set up modbus tcp devices in litmus edge devicehub step 1 set up and configure the plc device document the modbus rtu station addresses for each connected device on the rs485 multi drop network ensure your modbus rtu stations and the litmus edge gateway's serial or usb port are properly connected to the serial network verify the serial communication parameters (baud rate, parity, stop bits) configured on the converter match your rtu devices note the tcp port number configured on the converter (typically 502 for modbus tcp or a custom port) open the port for communication on the system > network > firewall > inbound rules page step 2 set up the plc device in litmus edge devicehub configure the following parameters when you connect a device docid\ pal6abpzbrimdu9lvgj30 with this driver update default values to the specific setup of your device parameter value type modbus driver modbus multi station rtu to tcp converter network interface 0 0 0 0 (or the ip address to bind the tcp server to) port 502 (or custom port to bind the tcp server to) max tcp connections 32 device file /dev/ttys0 baud rate 9600 data bits 8 parity none stop bits 1 response timeout 5000 (ms) retry count 3 pause between requests 10 (ms) calculate and note down the value from this formula number of stations × (\[response timeout × (retry count + 1)] + \[retry count × pause between requests]) if you are using the default values, the formula is number of stations × 20030 step 3 set up modbus tcp devices in litmus edge devicehub see the modbus tcp docid\ fdminjdckrjhg8uz0m9gf page and instead enter 127 0 0 1 in ip address field the tcp drivers should set the retry count to 0 and response timeout according to the value calculated above