one more plc5 question

I am looking at buying a 1771 SDN/C Rev.E01
And have a 1771-A4B B chassis.

in the user manual it says from what I read that the chassie needs to be 1771-A4B {C} . What is the difference?

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1771-um118_-en-p.pdf

Page 7 has the table that concerns me

Thanks Again,
Matt

I think that list is just "what we used in the lab", so the 1771-AxB Series C chassis were what was in production at the time. I think Series C was when they changed the plating alloy so the chassis are silver colored instead of the old gold color.

There's a detailed 1771 chassis history document in the RA Knowledgebase (Article ID 15463, TechConnect required).

Any 1771-A4B chassis will work with the 1771-SDN.

Only the "original" 1771 chassis, from before 1985, don't support 16-bit modules or block transfers, and therefore won't support the 1771-SDN. These part numbers were "1771-A4" or "1771-AC" and lacked the third "B" character. They're usually found only in very old PLC-2 installations.

The main reason for my concern was a I had bought a 1771-SDN/B and it worked for a week and then the Module status light went to the "O **** RED solid light". And cant find any reason it would do so. Have no idea if some how it can be reset other that sending it to AB..

Ken Yet again you are GREAT!!!!!
are you sure you don't work for AB?? lol
seems like you are as good as there knowledge base!!

Thanks Thanks again
Matt

Ugh, a solid red light is a bad thing.

This is the Module LED, not one of the Channel Status network LEDs, right ? What do the 7-segment displays do ?

If you're getting a solid red Module LED and the block transfers are failing, you definitely have a failed module. If this purchased on the aftermarket and doesn't carry a warranty, it's probable that it was damaged before you bought it.

It can't hurt to blow it out with clean air and clean the backplane contacts with alcohol; all the normal stuff you'd do to see if contaminants were causing the fault. Are there any other modules in the backplane that fail at the same time ?

(An aside; I worked for Rockwell Automation as a PLC specialist in a sales office for about thirteen years.)

Yes Ken the Module was working could see it in RSNetworX and the Chanel displays never shoe anything even at power up. yes I took it apart and blew and cleaned the unit. Still no luck. Just would like to figure out what went wrong will try again but not a big deal got it cheap.

Thanks Ken
Matt