local indication


Thread Starter

Fred Chwalek

I need to display 20, 4-20mA loop values locally, and remotely on an HMI. I currently have 20 Red Lion loop indicators mounted in a control panel to give local indication, and run an RS485 link back to an Opto22 controller and PC located in a trailer on site. The customer pointed out that 20 Red Lion displays cost more than some laptop computers, and couldn't we replace the loop
indicators with a flat panel display and/or CPU combination. Sounded like a good idea until I started pricing things. I have not been able to find a flat panel display and or CPU combination for under $2500.00. ( not even close ) This seemed a little strange since I can buy a Dell laptop for $1999.00 or less. The environment
is not hazardous, but it is literally a shed in the middle of a field, so it is not somewhere we would like to keep a laptop out in the open.
Does anyone have a suggestion.
Thanks, Fred Chwalek
If you're willing to write C code, check out the
PK2600 and/or OP7100 from ZWorld. We use both and have had good luck with them. Cost a lot less than $2500, but you'll be limited to 320x240 (quarter VGA) monochrome screens.


Industrial style stuff will alway cost more. Try getting the laptop and spend about $100 for a security cable to lock it to something big and
heavy in the shed.

Al Pawlowski

You might be able to do it for $2500 with a properly (I/O) configured RUG9 process computer, see www.rugid.com. This unit comes with a free drag and drop application builder that runs on Windows 95/NT so you don't have to do any traditional programming. I often use these for RTU's. Screen is about 320 x 240 also.

Tanweer Ahmed

What about an LCD or Luminous display OIU (operator interface unit). Horner Electric, Indiana, makes such OIUs with RS485 comm. and its very cheap. For use in an open space you may choose a luminous display rather than LED for
better visibility. Check http://www.heapg.com

Tanweer Ahmed

Dittrich, Rodolfo

Other things you can try, is a Magelis terminal (Modicon) that can communicate in modbus or modbus+ (RS485). There are different models and capacities for this. Regards