Hi everyone 
first of all sorry if my english is not going to be perfect, but I'm from Italy.
I'm having some troubles with modbus-contrib by @bianco-royal .
Basically, the connection to the server is ok, but I'm not able to read or write anything.
I've already tried a TCP-RESPONSE node injecting an hex buffer, and everything works good.
From the tcp/ip to rs485 device I can clearly see two connections from my client, just to be sure that it isn't a tcp-part problem.
I hope someone can help me..
Have a good day 
Here is my temporary flow:
[{"id":"dda328e3.b92f48","type":"tab","label":"Modbus -video Flow 1","disabled":false,"info":""},{"id":"d0aa07e1.8888e8","type":"modbus-read","z":"dda328e3.b92f48","name":"","topic":"","showStatusActivities":true,"logIOActivities":false,"showErrors":true,"unitid":"","dataType":"HoldingRegister","adr":"6","quantity":"1","rate":"3","rateUnit":"s","delayOnStart":false,"startDelayTime":"","server":"d0e85f54.82355","useIOFile":false,"ioFile":"","useIOForPayload":false,"x":210,"y":80,"wires":[["776f16c7.659548"],[]]},{"id":"776f16c7.659548","type":"debug","z":"dda328e3.b92f48","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":440,"y":80,"wires":[]},{"id":"11acc744.0ef1a9","type":"inject","z":"dda328e3.b92f48","name":"unit address","topic":"","payload":"00 03 00 06 00 01 65 DA","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":170,"y":180,"wires":[["eec4ff8b.d0f49"]]},{"id":"eec4ff8b.d0f49","type":"function","z":"dda328e3.b92f48","name":"","func":"bufferInput = msg.payload.replace(/\\s/g, '');\nmsg.payload = Buffer.from(bufferInput, \"hex\");\nreturn msg;","outputs":1,"noerr":0,"x":350,"y":180,"wires":[["bc01da87.1739a8"]]},{"id":"bc01da87.1739a8","type":"tcp request","z":"dda328e3.b92f48","server":"10.0.1.168","port":"8233","out":"sit","splitc":" ","name":"","x":540,"y":180,"wires":[["12ea9d53.4ed583"]]},{"id":"12ea9d53.4ed583","type":"debug","z":"dda328e3.b92f48","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":780,"y":180,"wires":[]},{"id":"d0e85f54.82355","type":"modbus-client","z":"","name":"","clienttype":"tcp","bufferCommands":true,"stateLogEnabled":false,"tcpHost":"10.0.1.168","tcpPort":"8233","tcpType":"TPC-RTU-BUFFERED","serialPort":"/dev/ttyUSB","serialType":"RTU-BUFFERD","serialBaudrate":"9600","serialDatabits":"8","serialStopbits":"1","serialParity":"none","serialConnectionDelay":"100","unit_id":"1","commandDelay":"1","clientTimeout":"3000","reconnectTimeout":"2000"}]
