Premium Modbus Comms, using ethernet gateway

[rajsiyer 7]

Hiya Friends, Wishing you Jolly, good Christmas. Have a blast over a great week-end & good new year!! However, please take your time to answer this one & I'm in no hurry. Using a Premium 57234, I wish to read Input-register(ie. address range 300001 words) from flow-meters which are Modbus-serial slaves which have a ETG-100 polling them as master and communicating with the Premium on the ethernet side. Question fellas, is what communication functions support this?. Am I wrong in thinking that IO scanning service on the Premium-PLC's ethernet port CANNOT be used for reading INPUT regs. on the Modbus slaves?? Also, how does one incorporate the slave (behind the gateway) address + slaves' starting addresses in the SEND_REQ function's syntax?? A million thanks for looking in while on holiday season. Regards, best wishes, Raj S. Iyer

[aggattapauer 2]

Raj S. Iyer, Merry Christmas and happiest new year.. I/O scanning supports only modbus function 03, 06, 16, 23 (so cannot read %I and %IW) (that's for all Schneider PLC's) the address is made of 5 words... = MET (ety slot, modbus slave address), IP1, IP2, IP3, IP4 in the EMIS parameter you have to program the modbus string (6 words) to send to the slave modbus function modbus request (16#0296) reserved starting slave address length number of bytes to send (10 = 5 previous words x2) **Remember that sometimes you need to swap the received bytes

[billysmithde2 1]

How do you get FC 06 out of IOscanner? I can only get 3, 16, and 23. If 23 fails, it breaks it down to 16 and then 3 even if it is a single write register, or just uses 16 if it only a write. Is there a particular combination of register counts or addresses to get it to use FC 06?

[rajsiyer 7]

Thanks Billy & agatta, Thanks a lot indeed.I really am obliged that you took time out on Christmas weekend to help me out. Merry Christmas to both friends, once again. Raj S. Iye

[koyeap 0]

Hi Raj, Instead of using I/O scanning, maybe you can try DATA_EXCH? it can send modbus command through TCP/IP, so reading I reg seem possible. It work on M340 but no sure it will work on premium Hope this help Yeap

[aggattapauer 2]

no, FC06 is supported by some communication functions such as WRITE_VAR