Created Date: April 15,2005

Created by: EdWood

Hi all-

I have panel voltmeter that I want to use off the PLC. It displays to voltage 1-1, so I need to have a range up to 12V. I am using it to display the height of an object driven by a gear, which generates a pulse every revolution. Putting this info into a counter, I would like to use the counter value divided by some factor to output the corresponding voltage. For example, if the device were 6 feet high, the PLC would output 6V and the meter would read 6.

Ideally, I would like the PLC to output in realtime so that the numbers on the meter go up as it the device moves. (It can only be moved in 3ft increments.) I have basic ladder logic programming skills but I'm not sure how to do this.

thanks!

-Ed

Created Date: April 15,2005

Created by: Gerry

12V isn't a standard output voltage from a PLC.

Which PLC and analog out are you using?

I would buy a new meter that reads a standard signal that's 0-5v, or 0-10V, or 4-20mA, I prefer 4-20mA. Cost is about $200-250, or use an EZ-Text.

Then your PLC will have no problem signaling the meter.

Or you may be able to find a signal converter from standard to 0-12V.

Otherwise it looks like you have a solid plan!! http://forum1.automationdirect.com/board/smile.gif

Created Date: April 15,2005

Created by: EdWood

I am using the DL-05, which is speced out at having a 6-27V output. I assumed (perhaps wrongly) that I could tell it exactly what voltage to output.

The meter itself will read from 0-27V, and since I want to display from 0-12, it seemed to be a good choice.

Looks like I'll have to get a new meter either way, but can you tell me how exactly to vary the voltage on output? Maybe I'll get a little text meter, in which case, is that also an easy programming step?

thanks a lot,

-Ed

Created Date: April 15,2005

Created by: EdWood

I intended to use a proximity sensor to measure the revolutions, though I'm not sure the one I have will work with the PLC anymore. The resolution of 1 rev is fine, as this thing is to move up in 3ft increments and it moves .1 " every revolution. That degree of accuracy is aceptable.

As for handling the direction, I tell the PLC to set 1 of 2 directional outputs to on (while resetting the other) based on input switch postion. In this way, I use the output as one of the variables in an up down counter, so it moves up or down accordingly.

The only reason I orignally strayed from an encoder option is we weren't about much of the mechanics at the time ( a few months ago) and the proximity switch seemed the best choice, especially since there is still a good chance that the sensor will get pretty dirty (saltwater & hydraulic fluid).

Ok that being said, I looked at the text panels from automation direct and they are just too pricy. I am trying to find a panel mount up/down counter with scaling that I might be able to tell up or down with the signals I mentioned above and then sending the sensor output to both the plc and the counter.

Does that seem like a good idea? Or should I possibly scrap the proximity sensor and use a cheap encoder?

Sorry for all this info...just getting down to the wire here and trying to find a solution fast.

thanks,

-Ed