AB 1760 help...

dwainej · Sep 25, 2008

Gentlemen,

I have a project that I have inherited from a co worker that recently left and in which he was about mid way through completion. I have been left with trying to figure out his thinking in building it the way he did and using the parts that I have been left with.

Project: We will be trying to use an AB 1760-12BWB as a safety switch for a TVAC chamber (in case of a loss in pressure we can quickly shut down our unattended electronic equipment being tested). Other equipment he purchased for this was a Hornet IGM-401 vacuum gauge. I have been able to finish wiring up everything and get it to work electrically as well as see the gauge work under pressure.

At this point I am in the process of hooking up the analog output from the gauge to the 1760. The output voltage from the gauge will represent the Torr on a scale of 0-10vdc (ie.. 1.0E-07 = 3.0vdc). Inputs (I7 and I8) on the 1760 are setup to read 0-10vdc but I can not get them to read anything less then about 8vdc. In searching the forum, I have read about an analog input module. one question I have is, do I need one in order to get the controller to work correctly or does the 1760 already have that built in? AB’s documentation is not as helpful as I thought it was going to be…

Any other ideas, thoughts or even suggestions, on this would be helpful as well as greatly appreciated!

Dwaine

Chris S · Sep 25, 2008

Searched for this part number on AB website. Didnt find. I cant remeber all of the part numbers so if you can, I'd like to know what this is. Is it a Micrologix? A Flex I/O module or some kind of remote I/O thing. Is this a guardlogix PLC or something like that?

Just a bit of info on what this thing is then I can look it up for more info tommarrow when I get back into work.

Tim Ledwith · Sep 25, 2008

Dwaine,

Is the Vacuum guage loop powered or do you have to put a seperate supply onto it to drive the 0-10V back to the Pico Relay ?

Tim.

dwainej · Sep 25, 2008

The vacuum gauge is powered via the same PS that is powering the pico controller. I can read the voltage from the analog output (at pressure) via a DMM and right now it reads 3.7vdc which equates to 1.0E-7 torr. The problem is that I can not get the controller to see the voltage on the display. The numbers on the pico display (input 7 or 8) do not come on till the voltage reaches about 8vdc.

I am tying the analog output ground wire (from the gauge) to the PS supply ground and then the analog output voltage (from the gauge) to input 7 or 8 (on the controller) and the controller will not acknowledge an input. With a seperate adujustable PS I can get the controller to see voltage (the number 7 or 8 comes on) right around 8vdc.

The pico controller is a 1760-L12BWB

Mickey · Sep 25, 2008

Chris S said:
Searched for this part number on AB website. Didnt find. I cant remeber all of the part numbers so if you can, I'd like to know what this is. Is it a Micrologix? A Flex I/O module or some kind of remote I/O thing. Is this a guardlogix PLC or something like that?

Just a bit of info on what this thing is then I can look it up for more info tommarrow when I get back into work.

http://literature.rockwellautomation.com/idc/groups/literature/documents/pp/1760-pp001_-en-p.pdf

Ken Moore · Sep 26, 2008

I didn't think any of the PICO line was rated for a safety shutdown system, am I wrong?

mordred · Sep 26, 2008

No I beleive your correct leastwise none of the PICO series I've seen were rated as a safety PLC

Chris S · Sep 26, 2008

dwainej said:
The vacuum gauge is powered via the same PS that is powering the pico controller. I can read the voltage from the analog output (at pressure) via a DMM and right now it reads 3.7vdc which equates to 1.0E-7 torr. The problem is that I can not get the controller to see the voltage on the display. The numbers on the pico display (input 7 or 8) do not come on till the voltage reaches about 8vdc.

I am tying the analog output ground wire (from the gauge) to the PS supply ground and then the analog output voltage (from the gauge) to input 7 or 8 (on the controller) and the controller will not acknowledge an input. With a seperate adujustable PS I can get the controller to see voltage (the number 7 or 8 comes on) right around 8vdc.

The pico controller is a 1760-L12BWB

So the inputs are actually selected to be analog inputs correct?

Because you can use those for digital inputs aswell according to the lititure. Also this Pressure transducer or vaccum transducer is a 0 - 10 VDC analog signal right.

Not real familiar with the pico controller but as I understand it it seems to be acting like the input settings are correctly set for the controller. Like its set for digital or set for some other kind of range. But seeing how its only 0-10VDC on the pico controller I'm assuming its the sensor or the digital/analog switch that needs looking into.

Also if you are going to do more of these you might want to think about using a guardlogix for the saftey rating.

AB 1760 help...

dwainej

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Chris S

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Tim Ledwith

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dwainej

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Mickey

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Ken Moore

Lifetime Supporting Member

mordred

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Chris S

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