GE 90/30 360cpu

Hi, I'm hoping someone out there can help me. I have a ge 90/30 plc running a 360 cpu. My problem is that when there is a power disruption all outputs are disabled and the run light on the powersupply flashes. I also cannot communicate with it at all. The strange thing is, after about 2hrs it all seems to reset itself and goes back to work???

Replace the Power Supply. It has a bad capacitor that needs to get hot enough to start working. That takes about 2 hours in this case.
The flashing lights and disabled outputs is caused by one or more of the voltages being low. After the cap warms up to 'normal', the voltages are high enough.

Thanks very much Keith I swap out the p.s and see how it goes.


Regards, Jo

Back again. No luck with changing out the power suppl. The same problem still exists. Anymore tips?

Jo

Give more details on the power disruption sequence. Is there a UPS on the system? Maybe it's supplying noisy power until it's batteries charge. Check the power input.
If it's not the power, then I might say CPU, but I have a hard time believing a CPU could have this kind of fault.
Steve is the GE expert. Wait for his comments.

I didn't respond yesterday because I figured Kiethkyll had called it correctly.

The RUN LED on the power supply blinks while the CPU is going through its power-on self test. For it to stay blinking for two hours suggests that it repeatedly fails that self-test and reinitiates it. To me, that points to a power issue. Since replacing the power supply didn't help, the next logical choice is either the CPU module or the baseplate.

Befor you replace any more components, check your power consumption. The manual GFK-0356 lists the power consumed by each module. The standard capacity power supply (IC693PWR321) is good for 30 watts, distributed among the 5 VDC backplane supply, the 24 VDC backplane supply and the isolated 24 VDC supply (that's the DC terminals on the PS available for your use). Each of those three is rated for 15 watts, but the total can't exceed 30 watts. There is also a high capacity supply (IC693PWR330) that can supply 30 watts on the 5 VDC. It's still rated for a maximum of 30 watts total.

Also check your primary power voltage level. The spec for the IC693PWR321 is 100 to 240 VAC.

I had a similar call from a customer a couple of weeks ago.
After it comes up check the Fault Table, in our case it indicated 'Los of I/O module' and pointed to a bad I/O module that was causing the problem.
After replacing it all was well. If ther is not faults, do the 'process of elimination' thing.

Hi all, yes the system does have a ups. The battery level on it never seems to reach full charge.. We eliminated the ups to see if it is the culprit but no change.

The sequence of events that led up to the problem are as follows:


1.Power loss (possibly due to lightning strike but not 100% sure). Out for approx 4-5 hrs. Also blew up separate regulated 24v pwr supp. in same cabinet.
2. Power restored. Power light on plc power supply on solid. The run and ok lights blinking at a constant 1sec interval.
3. No comms available
4. After approx. 2 hrs system reset on its own accord and functioning normally.
5. Subsequent power losses result in the same issues. Seems to be taking longer to come back after each loss.

Checked supply volts- constant 112Vac input to power supply. 24Vdc on front of power supply.
only 3 modules being used ic693mdl645, ic693mdl940, ic693alg442. It has been that way since installation 7 years ago.

Sorry for the long winded reply
regards Jo

Does it show the same symptoms with no I/O modules installed?

I'm leaning towards a module dragging you down. Try removing the terminals from the modules and powering up. If you still get the same results, try removing the modules one by one.

The normal power up sequence is for the OK LED to blink for a few seconds, then go on continuously along with the RUN LED. The fact that the RUN LED blinks, suggests to me that as soon as the PLC goes into run mode, something starts drawing excessive power, which drops the PLC out of run. When the PLC stops running, all outputs turn off. When the outputs turn off, the power returns to normal levels. This re-initiates the power-on self test and the cycle repeats.

We removed all the modules , thinking that something was dragging it down. Then repowered. The lights on the power supply went back to blinking. Could it be a short in the base plate?

Jo Mitchell said:

Could it be a short in the base plate?

Click to expand...

Yes, or a problem with the CPU.
Have you checked the fault table?

Could it be a short in the base plate?

Click to expand...

Yes

Also, do you keep your serial communications cable and your RS232/RS485 converter plugged into the port? The cnverter gets its power from the port. It's only supposed to draw 100 mA or so, but if it was damaged, it could also be a culprit.

RussB said:

Yes, or a problem with the CPU.
Have you checked the fault table?

Click to expand...

Russ, not as yet. Will do so as soon as I am able to get comms with cpu again.

Is there a way to test the base plate without swapping it out with another(no spare)?

Steve Bailey said:

Yes

Also, do you keep your serial communications cable and your RS232/RS485 converter plugged into the port? The cnverter gets its power from the port. It's only supposed to draw 100 mA or so, but if it was damaged, it could also be a culprit.

Click to expand...

Steve, no we don't.