Micro850 with Analog Outputs Module - No Output Signal!

Greetings,

My company is working on a panel for an OEM and it is the first time we are using the Micro800 family - specifically the Micro850 with one Analog Input module and one Analog Output module.

The panel is built and we are trying to test everything and for some reason we can't get the analog outputs to output anything.

Has anyone seen this before or have any suggestions?

Thanks,
Phil

Did you configure the 2085-OF4 for the proper Min/Max Output range? Is it wired appropriately?

see page 36 and 20 of :
http://literature.rockwellautomation.com/idc/groups/literature/documents/um/2080-um003_-en-p.pdf

Thanks for the response.

Yes - it has been configured to 4-20mA in CCW and it is wired accordingly.

So even without simulating any actual values, the minimum should be at 4mA but we are reading 0.

It sounds like you might not have power connected to your OF4 COMMON trminals. Without power, you will get 0 Output values.

Commons are wired OK.

Called AB and .. turns out that if the analog outputs detect an 'open wire', like what you would get if you tried to measure them (closing the loop) and then removing the multimeter leads (opening the loop once more), the PLC generates a fault and that fault needs to be cleared before any other output signals can be sent.

Seems like a very strange way to do it to me. Not to mention this particularity is not very well documented.

Like many others, we have had a mostly-negative first experience with these Micro800 series controllers.

Thanks for the replies !

Like many others, we have had a mostly-negative first experience with these Micro800 series controllers.

Click to expand...

Thanks for the heads-up. This type of experience is priceless information for someone making a decision about which PLC to buy.

I've had a similar problem with an 2085-OF4 module today working on a job site. The module would not output 4-20mA despite checking and rechecking the settings. Out of frustration, I tried resetting the module to output 0-10V, and it seemed to work.

Is this problem, where you have to reset the module to get a valid output, still a problem on recent 2085-OF4 modules?