Communication of 3g3Jx with SCB41 with Protocol Macro

[nasir_ash 0]

Dear Team could you please help me, can SCB41 can communicate with 3g3JX inveter with out using protocol macro? regards NASIR

[Michael Walsh 268]

If you already have an SCB41, why would you not use the protocol macros that are already written?

[nasir_ash 0]

Dear Michael i want to communicate it via Rs485 without protocol macro using TXD and RXD command. could it communicate? regards NASIR

[GreyWolf 0]

If you have the 3g3jx user's manual read Appendix #2 - Communication function . If you don't have 3g3jx user's manual and SCB41 communications modes read the two pdf files I've attached . catalog omron 3g3jx.pdf CQM1H-SCB41.pdf

[nasir_ash 0]

Dear Grey thanks for the manuals. If we see the SCB41 Manual it shows that there is a NO PROTOCOL Setting for TXD and RXD. but when we look at PLC Settings, there is no such setting availabe. as shown in the attahced, This make me confuse. can you please help regards NASIR

[Jay Anthony 118]

NO PROTOCOL = RS232 in PLC Settings

[nasir_ash 0]

Dear Jay TXD and RXD converts the data to ASCII and then transmit and recieved. but the 3g3jx communication setting shows that Data bit length= 8 bit Modbus RTU ( ASCII mode not availabe) can we do data tarnfer in that case? regards NASIR

[Jay Anthony 118]

TXD and RXD can be used for both ASCII and RTU binary. It does not "convert the data to ASCII". It sends the literal hex codes of ASCII which can also contain RTU binary.

[nasir_ash 0]

Dear Jay make a ladder logic for with TXD and RXD commnds. when i turn ON the TXD the port 2 SCB41 turn ON, inveter also behaves that it is communicating with the SCB, and No communicaton alarm on the disply of inveter. i am trying to turn ON the coil to RUN the inveter, but it is not please find the attahced command format descriebed in the 3g3JX manual and also the PLC program. please review it and suggest what should be the exact command format to enable the inveter to come at RUN mode regards NASIR TXD-RXD CQM1.cxp

[PMCR 66]

NASIR The TXD / RXD commands can send both ASCII and Binary data out the serial port, and also receive either ASCII or Binary data back in the serial port. The problem with using TXD / RXD for Modbus is that you must calculate the CRC16 Modbus checksum for each command or response in ladder. This can be done, but it is very difficult. PMCR has the ability to calculate the CRC16 checksum for you. In general, Omron recommends using Protocol Macro for Modbus RTU, because of the CRC16 calculation capability. Jay Anthony is one of the Omron pioneers in Modbus RTU communications. I have deferred to his Modbus RTU judgement and guidance many times over the years. I think that Jay will agree that Protocol Macro is a better way to go for Modbus RTU. PMCR

[Michael Walsh 268]

PMCR, that is very nice of your to volunteer. When did you start referring to yourself in the 3rd person? By the way, I agree with you. I tried to steer the conversation that way early in the discussion. Edited 1 Apr 2011 by Michael Walsh

[PdL 71]

Guys, know what you get yourselves in to...

[nasir_ash 0]

Dear Michael i am totally agree with you that PMCR is more eaisy to use annd work. but here a question rasied, for those PLCs which are not compatible or not support PMCR, so how these PLCS work with RS485 or Modbus communication How CRC16 calculated for these PLCs. so i need your help to communicate the PLC with 3g3jx with out using PMCR. regards NASIR