problem pulse reading with fast counter card in NX2

[CX_Luigi 1]

together with colleagues we are setting up a system in which a flowmeter pulse output is read by a NX2 plc with a fast counter card EC0222. We found a very significant discrepancy between pulse count from flowmeter and the value read by the card, on the order of tens of liters. We replaced the counter card with others, just to be sure there is no faulty hardware, but the result does not change, and in Sysmac Studio there are no settings for the counter card that may correct this error. The same flowmeter with same pulse setup is read perfectly by a CJ2 cpu equipped with CTL41 fast counter card and that makes us very perplexed. Do we have to resort to filtering the incoming pulses in the card, or there are settings we can make in Sysmac Studio to improve the situation? This system is one of the first we are doing with the new NX2, and in the past using the CJ types we never encountered this kind of problem.

[lostcontrol 23]

Interesting, we are also experiencing similar issues that we have been unable to solve with the NX modules.

i have a few thoughts, but nothijg concrete as yet.

[Crossbow 295]

When you are on the NX configuration screen, click on the module and there is a button to the right (or right click) for 'Edit Unit Operation Settings'.  All configuration of the card is done there.

NX-EC0222 can count 500KHz.

[lostcontrol 23]

The NX-ECO can count 500 kHz yes, but it can’t do any filtering of any noise is present.

[chelton 66]

 

So for accuracy using NJ/NX controllers is it safer to stick with a CJ1W-CT021?

i have a dosing system coming up that I was planning on using NX I/O

[lostcontrol 23]

At this stage, perhaps. What frequency will you be requiring to count at? 

It is possible that you might not have the noise/interference we have experienced, but is a hard one to determine

[chelton 66]

Im only after 4khz max.

 

[CX_Luigi 1]

acting on advise from Omron support, we replaced the EC0222 with a GX-EC0211 card and the problem disappeared. We had to act quickly as we were near shipping date and we had no time to consider alternatives, but it was somewhat of a disappointment especially considering that Omron pushes a lot NX I/Os as the preferred alternative to Ethercat couplers, and we have already several projects lined to use them. Now we need to consider their use carefully

Edited 22 May 2018 by CX_Luigi

[lostcontrol 23]

Interesting. The only difference I can see is that the GX variant has a higher frequency capability?

Still no adjustments though..?

[chelton 66]

@CX_Luigi what is the maximum frequency you could reliably measure?

[chelton 66]

I wonder if other NX I/O cards either side of counter could interfere? 

[lostcontrol 23]

possibly, but also unlikely.

One setup we have has only a single IOLink module..

[CX_Luigi 1]

11 hours ago, chelton said:

@CX_Luigi what is the maximum frequency you could reliably measure?

Flowmeter pulse output maximum frequency is 2 kHz, and we normally set the pulse just at this value.