Hi All,

I'm looking to have some input on a design for a simple output testing device.

We install multiple machines that have variations of outputs, the outputs range from 12 v AC/DC to 230v AC/DC. I would like to create one box that has LED's to identify each output from the different machines. The LED's will need to work with all the variations of voltage without any changes to the test box.

Your help will be greatly appreciated.

 

Sounds like a lot of expense and work to
replace the functions of a ~$10.oo DMM from Harbor-Freight or Walmart.

Get a "Squealer-Stick" for the High-Voltage-AC.
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This is where knowing budget would help. Personally I was fortunate to have an employer with deep pockets so design and build of MATE (Modulator Automated Test Equipment) was never a problem. Would voltages be a yes, no or have a window for pass fail criteria? I would start with a blank sheet of paper and pencil with a big eraser. List your pass/fail criteria and tolerances. Then think about using transducers. Transducers get you from what you have to what you want. Again budget?

Ron

 

If I needed to convert a wide range of AC/DC voltage to a safe level, I would need to define: What is a safe level?
12 - 220 Volts at a mV scale could be 1.2mV - 22mV low current and that range may need individual dividers.
If individual dividers is the way to go, the next logical step might be sequential sample such as CD4017 Astable multivibrator.
The clocked CD4017 continues to sequentially sample. For 12V it stops at 1mA, for 220 it is 22mA current sensed comparator goes low.
What I am saying is the voltage across the current sense resistor is 1.2mV then the comparator output goes high

Only a qualified technician should attempt the high voltage.
When 220V is applied to the 12V divider it results in 22mV 22mA requiring 5W resistors
Ohms law gives resistor values for 12V divided down to 1.2mV at 1mA R1=12k R2=1.2Ω also Reference 1.2 mV @1mA

The resistor divider board uses the 1.2mV as reference should work with a micro controller but the cost
might exceed a DMM. There are other ways, not sure why a dedicated monitor needed but need to keep an eye on the robots.

 

I suggest an auto-ranging meter, or possibly two of them, along with a processor module and a barcode reader.
The plan would be to scan the barcode and then connect to the supply and get a meter reading, which then is compared within the processor to the specifications of that model.
Of course, a much better scheme will be to scan and then have the specifications appear on the screen, followed by the actual readings.
The box described in post #1 would be for use by an unskilled person who would certainly be an detriment to the organization due to their lack of skill.
The concept of not providing adequate information , by not displaying actual numbers, indicates a lack of respect for the client.