Modicon Quantum problems

[Jim Dungar]

Grounding and termination problems usually show up several years after installation due to the normal "corrosion" of the loose connections which eventually makes a marginal installation bad.

I agree with curlyandshemp, you need to download the RIO manual.

The Quantum can trap error codes. You use the STAT function to access a table of 277 words that provide processor information.

 

[darrenj]

2 things come to mind..First there is something about the coax being a minimum of 3' long..(This was told to by modicon tech support one time..dont remember why..)

The other is the back plane.. i have a couple fail right out of the box..others have waited for a while.. The other thing is has anyone checked the address of the drops?? make sure there is not 2 the same..Most of the time one rack just wont work but that depends on what rack power up first...


BTW
I have seen installations run just fine with out the termination resistor..

 

[Jim Dungar]

The minimum tap length has to do with the wave length of the signal. This distance along with the terminating resistors prevents reflected wave problems.

 

[OZEE]

I was told the minimum length was 10'.

Well, we rerouted the coax this morning. And so far, so good.

They did tell me that once it ran for three weeks after one "fix", so don't know how long we'll have to wait to really know. The other day after I put in the terminating resistors, it ran 20 minutes. We're already past that.

Now that I'm posting this, I probably just jinxed it...

I suppose that if it drops out again, we'll have to look at replacing the rack. Don't have one of those on the shelf, so we'll have to order it if needed.

Thanks for all the suggestions!!

 

[OZEE]

Arrrrgggg

It did it again -- but this time, it was a different rack. I guess that's good??

This time, I did observe the COMM light on the RIO module flickering. Also, the CRP was displaying the ERROR A light. Guess we'll keep looking...

 

[curlyandshemp]

Arrrrgggg

It did it again -- but this time, it was a different rack. I guess that's good??

This time, I did observe the COMM light on the RIO module flickering. Also, the CRP was displaying the ERROR A light. Guess we'll keep looking...

Next time count the LED blinks to get the type of error code