CVS with VBAI Inspection Fail (Pass) signal

[tiocan]

In my application the Inspection Fail (Pass) signals are not static but periodic. According VBAI documentation the result of each inspection remains stable and it is reset at the beginning of the next inspection. In my application this signal is periodic with a frequency about 4Hz depending of the number of steps I have in my script.

My application is an Acquire Image step with an external trigger on camera and some steps to measure a length, the Inspection Fail signal is used to eject or not  the part under examination. With an  Inpection Fail signal periodic it's quite impossible to eject properly the parts!

Does anybody knows a solution to this problem?

Thank you for your help.

(  I use a CVS1454 with VBAI 2.5 and Basler A601f camera)

[DOC (-) doc]

I am very interrested because I wanted to use this functionality but did not tried it out yet.

One way to overcome the problem is to "AND" the output with the "acquisition finished signal".

[DOC (-) doc]

Hi Tiocan

Another idea : is your camera Time out set to 250 ms ?

Because when you execute the script, when it gets at the acquisition step, if no trig is found before time is out, then you have a failed condition on that step, which means a False on the output, wich would give a 4Hz signal dependant on the number of steps.

Cheers.

Doc-Doc

[tiocan]

Hello Doc-Doc

The AND solution is not good, because we have only access to Inspection in Progress signal via an Output channel and this need an external circuit!

But your are right with the Image Acquisition TimeOut. The Inspection Fail signal is linked to the TimeOut value. This is a problem when your inspection rate is aperiodic: from several seconds to 300 ms. If you haven't any events during more than TimeOut, Ejection signal occur and can produce an undesirable trouble.

I find out that my CVS (or Vision Builder ) get some troubles during setting up of inspection steps: missing image inspection, Inspection Fail frequency whatever the Timeout value, image displayed on monitor remains the same even you change to the other camera in PC inspection, impossible to edit some step because impossible to get an image in PC, and so on. Only one solution : erase the inspection reboot PC and CVS and write again!

Thank's

[DOC (-) doc]

Hi Tiocan

What you describe is a general behavior when you work with rt systems (which is behind the CVS).

In the newest version of LV-RT, there IS a great improvements due to a better TCPIP layer. Thus this will soon improve the behavior of the CVS in remote mode. The image shown is a low priority process, so depending on the size if the image, it can be frozen.

Concerning the ejection signal : I don't want to do your application, but you should NOT AND the acquisition step result and the inspection result. Then it should not change status after each inspection time out.

Cheers.

Doc-Doc

[tiocan]

Hello Doc,

AND function can be done only in the external driver of Ejection by using 2 Output channels, and not inside VBAI with Decision making or Calculator! It's a pitty!

Do you think next version VBAI ( >2.5.1) will have LV-RT improments you are talking ?

I have visited machinevision.ch! Your are not so far my company. How can I join you directly ( perhaps in french)?

Thank's for your help

[DOC (-) doc]

no problem : send me your phone number using the e-mail adress you found on my site. Send it now because I am out of office this afternoon

[FRUSTRATEDIN_ALABAMA]

I have had the same problems....it gets worse it you upgrade to VBAI 2.6.1....the problem is that the output that you turn on when an inspection fails is a pulse, and the pulse width is very short....I have 1 application where the output is hardwired into a process plc and I dont have any problems...My other application I am pulling in a relay which is sounding an alarm (  or in your case rejecting a part )...

It worked fine most of the time, but at times the relay blinks ( pulls in but drops out before it seals in )  Replacing the " ice cube " relay

with a solid state relay worked better but not 100% of the time.....Unfortunately  it is not an option to increase the pulse width or make the output maintaining instead of a pulse...I have submitted this as an improvement for their next revision.....Other workarounds that would work if added as an option are  If / then statements  and timers in the decision block  or calculation blocks....but we dont have that function either...