That looks suspiciously similar to a variant of an old Motorola VME system.
If you are able to a) show the entire rack assembly and/or b) power down and pull the left-most card and take a picture we would probably be able to tell for sure.
Control systems without brand names or model numbers are just so fascinating to me, coming from A-B where we never skipped an opportunity to paint an octagon on something.
There's a contrast knob; where's the display ?
Can't be particularly modular if the analog input selectors are on the CPU module.
The top and bottom screws are VME-like, but all the VME modules I've ever seen are narrower and have those characteristic pull knobs at the top and bottom.
Since there is no brand name, logo or type no, then maybe this is a machine manufacturers custom controller.
Also, the 15 and 5 channels per module instead of the typical 8, 16 or 32 channels. Thats weird.
Due to Murphy's law I am sure this goes:
1. power down
2. pull out module
3. write down name of company that does not exist any more
4. reinsert module
5. power up
6. machine does not run any more
7. you get the blame for that
Check electrical drawing, BOM, event project documents, any manuals, or cable names, small part names. And ask an old employee about who came into the plant to install it.
Not all VME systems used the captive screw system, I have run across a couple of manufacturers that used their own face plates and double width installations, usually to make room for daughter boards.
The comment about Murphy's law is probably worth taking to heart, especially with the battery light llt up. I didn't think that one through.
It would still be really helpful to get some more pictures though, and perhaps a description of the machine itself.
Yeah and it'll go like this: One can't replace the battery (if and when one finds out where it is and what kind it is) without powering down, and then we lose the program which is irreplaceable. Just sayin'.
AB SLCs are like this. The rest off the PLCs have batteries front and center that you can change runnning. SLCs? no! You have to remove the processor card to change the battery. AB says you have 30 minutes after power down to swap batteries, but I don't trust them, no sir. I always upload the program before battery switch.