Hi guys;

I've never seen anything this before..

I'm connecting 4 Twido PLCs to Citect, using the driver(Modnet30) which is the one suggested by the express wizard of Citect(ver-7.0) during the course of adding a new device. Ok, lets say I've connected 4 twidos after they have been properly pinged; each on its IP address which is the same as entered in the wizard. Port Nos.,board nos etc.. Blah, blah all properly configured. Even the cluster and the network address all prior to this of course.

Now after pack+compile on Citect, it is run. The integers and real variables are all showing up nicely. You change any of these in Citect, and the animation tables in TwidoSuite on-line all show things work excepting for discrete variables in the project that is!. I've also observed that some date strings get shortened.

I change the protocol from Modnet30 to Modnet, the problem remains, I change the addressing notation for %Mi from 00001+i to 000001+i, no improvement. There is no clear guidance in either Citect or Twido Suite(Ver2.1) on how to do this correctly. A huge number of modbus on Ethernet protocol variants are available in Citect.

I get the feeling that perhaps it is the improper protocol selection or addressing notation which is to be corrected. Again, when does a particular %Mi become a modbus contact(requiring Input adressing notation ie %mi =10001/100001 + i) and when is it a coil ?( address =000001 =i)

Please help me out with this, so I can feel more secure about my PLC +scada system. At present I am unnerved and on the point of despair.

Any help will be sincerely appreciated.

Raj S. Iyer

as in my experience:
for modbus protocol you use Configure " Express Communication" :
Exeternal IO device -> Schneider Electric -> Twido -> ( you can choose modbus RTU or Modbus TCP) and next
in variable tag: in address:
40001-49999 for register out, you can write from citect to twido) ( for example : 40001=%MW0)
30001-39999 for register in you can read register from twido ( 40001=%MW0)
you try more with
00001 for %M0 out
10001 for %M0 in
Port is 502

Thanks ballvietnam;

All what you say is well known. This is the way modbus was . Thanks all the same. Problem was of a different nature

But the real reason was really unusual as I found out. This is something nobody tells you and is never found in any help menu or user manual! I hope you find this useful.

With Twido and that bad work of art ie TwidoSuite,,, there is one more thing you've to do.

Twido suite automatically allocates the number of %m and %mw objects to the plc application. In PL-7 you had a choice! so if your application has a highest address number of %m40 used in the program, Citect will not be able to read/write higher address ranges! As far as Twido is concerned %m41... %m255 simply are non existent, because these are unconfigured objects.

so if you put a meaningless rung involving %m255 the whole of the address space is available for comms.

Wish you all the best and shall request you to do your bit to dissuade Aussies from needlessly beating up us Indians!!! .

Raj S. Iyer