ab plc output life

Ok we have a lot of allein bradley micro 1500 plcs on or smaller machines they all seem to have started getting stuck outputs.

Does any know if there is so many cycles that they should last

What type of output are you talking about?

Relay outputs are generally shorter lived than solid state outputs, but there are things that can be done to extend that life.

Tell us more about the application (number of cycles, type of output, type of connected loads)...

Paul

they are relay outputs.

On these machines they control air valves and hydrolic valves.

They cycle an average of 50 times a hour 24hours a day 5 days a week.

I was just curouis becouse right now it seems as if 1 a day on 350 plus plcs and they are all built around the same time frame

I could not find specifications for that particular relay output, but I typically expect about 500,000 cycles from a relay contact. That's about 1.6 years for your case. You can increase the life expectancy by adding surge suppression to the solenoids you are driving, or switch to solid state outputs if possible.

Going to solid state outputs could definitely increase the life, while adding surge suppression to relays is more likely to prevent early failure, but they'll still wear out eventually.

I have a customer with a similar problem: Micrologix 1500 with relay outputs driving solenoid valves for hydraulic presses. On & off all day. Turns out the relay contact was rated at the same number of amps the valves drew. I installed interposing relays and never had another issue. PLC output turns on relay, relay turns on valve. I used the Finder relays that are the same size as a terminal block.

use a relay, however will give same problem, we had to put all VDR on the outputs to prevent sticking.
try the following take a small relay and your valve set, if you see any spark, then take a VDR or spikecontrol and look again.
you could use a oscilloscope to see what happens.
if problem send or mount these devices.
If all outputs go to terminals, buy new terminals with this built in, like wago, phoenix or any.