RS485 SSI Protocol

I hope you guys can help. I have a customer with a machine that has a Nord VSD on it the drive has died and is obsolete. I am trying to work out what the communication protocol between the PLC and VSD is. I do not have the PLC software (it is a Dias). The drawings for the machine show the output from the PLC card as RS 485+SSI. Any tips on nailing down the protocol would be greatly appreciated.
Thanks

model of drive could be useful

Also the RS485 Board

also model of PLC

The brand of drive is Nord
http://www5.nord.com/cms/en/product_catalogue/drive_electronics/pgop_drive_electronics.jsp
The PLC is a Dias
http://www.sigmatek-automation.us/eng-product-quicksearch.html
Thanks

the model number should be on the side of the drive or PLC

RS485 can be using modbus plus a whole lot of other protocols
SSI is an encoder protocol

Depending on the PLC system (S or C or P) could change what we tell you

is this manual in the right direction?
Is this Card installed on the drive? BU4010
https://www5.nord.com/cms/media/documents/bw/BU4010_GB_0400.pdf

Note: it can receive SSI for setpoints


On the DIAS side what is the card Part number that it connects to?

Looking for some clues as to what is installed

Yes Michael that looks like the drive but it does not have that card. The VSD model is a 37kw SK37000/3 KG. There does not appear to be any additional cards installed other than the RS 485 connection to terminals 21 and 22 as on the standard drive according to the drive documentation. I will check in the morning and get the numbers for the PLC output card and model number
Thanks

I managed to get some more info on the PLC DCC 082 Dias-DKL095 and there are 2 input and output cards DKL12 and DKL13
Thanks

ktmtragic said:

I managed to get some more info on the PLC DCC 082 Dias-DKL095 and there are 2 input and output cards DKL12 and DKL13
Thanks

Click to expand...

ok getting closer
the DKL12 is the connection board for a digital module eg DDM 164
http://www.sigmatek-automation.us/eng_product_quicksearch/eng_quicksearch_pdf/eng_DKL_012.pdf
http://www.sigmatek-automation.us/eng_product_quicksearch/eng_quicksearch_doku/eng_DIAS_DDM_164.pdf

The DCC 082 DKL 095 I could not find
If I assume that DKL 095 is the version before DKL 096 which has the processor DCC 084
Then this looks like it may be a basic processor and is most likely using RS485

The closest that I could find is the DKL 096 and DCC 080-L
http://www.sigmatek-automation.us/eng_product_quicksearch/eng_quicksearch_pdf/eng_DKL_096.pdf
http://www.sigmatek-automation.us/eng_product_quicksearch/eng_quicksearch_pdf/eng_DCC_080_L.pdf

I think that this was a cheaper system installed some time ago.
I suspect that the RS485 was using the siemens protocol USS - this I guess from the Drive and the simple CPU (a high end CPU doing very accurate Motion is typically used for SSI protocol)
https://cache.industry.siemens.com/dl/files/253/24178253/att_101238/v1/uss_24178253_spec_76.pdf

If it is using the USS protocol then a siemens drive uses that HOWEVER the parameters that are in use on the PLC are hard coded and are very likely not to match - EG parameter 10 is Speed on the Nord and parameter 10 is acceleration in a siemens

I'm all done with the information that you have given me

If nord in melbourne cannot supply a replacement drive then you may have to replace the drive and PLC

Thanks Michael

You are bang on the money! The095 and 096 modules look identical. The output to the Drive is simple. There are no encoders on the motor so I agree in thinking communication is USS.
Thanks for your help it is much appreciated