Powering a 1771 card without chassis?

[arpus4KM]

Anyone ever attempted to power up and test a plc2 or plc5 communication card or otherwise using a power supply attached to the PCB edge? I haven't been able to find the specific voltage used or pins used to do this without a chassis/backplane. This is basically just for experimentation purposes, I could spend 40-50 for an 1771-A1B off ebay, but if I can save 50, then I'll save 50.

 

[Steve Bailey]

I find it hard to imagine what you would learn that way other than you didn't let the smoke out. The function of the modules that reside in the rack is to exchange information between the CPU and the rest of the world. Any test that doesn't include that aspect of the module's function is incomplete.

 

[arpus4KM]

I find it hard to imagine what you would learn that way other than you didn't let the smoke out. The function of the modules that reside in the rack is to exchange information between the CPU and the rest of the world. Any test that doesn't include that aspect of the module's function is incomplete.

Well, I'd agree normally, but some cards come as a Non chassis unit, which are actually just Chassis mount units, put into a case with a power supply added to the board. If it's something like a 1771-KF, it has a power supply to allow external use off a chassis to power it. whereas a 1771-KG has no power supply or backplane function, and just uses the 3 front ports on it to bridge comms.

 

[Ken Roach]

Point well taken, but I worked on PLC-5's for decades and never once attempted to pin out the backplane card connectors. It's not like it's a secret, but the need to power up a 1771-KF without having an -A4 and power supply handy is so infrequent I've just never seen someone try.

 

[arpus4KM]

Point well taken, but I worked on PLC-5's for decades and never once attempted to pin out the backplane card connectors. It's not like it's a secret, but the need to power up a 1771-KF without having an -A4 and power supply handy is so infrequent I've just never seen someone try.

That's pretty much why I said it was only for experimentation purposes. In my quest to understand some of these older systems I figured it would be useful if I could use something like the KF/KG as an external communicator without needing to haul around an entire chassis (and man those were heavy) just to power up 1 card.

Much nicer to throw a 5vdc power supply or usb power adapter on it since the other external cards take a 5vdc power input to operate.

 

[jasil]

It was the rack.

Thanks Ken you have helped 1000s over the years.

 

[alan_505]

It was the rack.

Thanks Ken you have helped 1000s over the years.

Jasil wrong thread.