With everything disconnected to the meter, I get zero Ω across the +- of the current input on the back of the trumeter. I checked it with 3 different DMM. I checked the input next to it which is the voltage input to see what it was and it was also zero Ω. Possibly this is a bad meter from the factory.

Sense the CT seems to be working right, (is it normal for it to be 4.8mA instead of exactly4?) and peaks out around 22 mA at startup, I am thinking its something with this meter. I have gone over my wiring so many times, like you said its fairly simple. When I put a DMM in place of the trumeter I am getting close to the correct mA readings that I should be. So if things were wired wrong I wouldn't see something else or perhaps nothing at all.

 

Then that leads me to believe a problem with the meter, just as you say. While the resistance across the meter should be about 15 Ohms as I see it you are getting nothing even close. That makes no sense and as you say, you have been over this a dozen times. I am at a loss as to what to tell you.
Something we could tray is if you have a 500 Ohm resistor we could run the current loop through the resistor. The voltage drop across the resistor should be about 2 to 10 volts and you could try feeding that into the voltage input terminals of the meter.

Ron

 

I called the manufacture and explained everything and had to go over every connection and what tests I did and the engineer confirmed that across the current inputs there should be 15Ω. Mine shows nothing, no continuity at all so something isn't working wright with it. They said they will replace it but wanted a diagram how I hooked it up so I made one and sent it to them. So ill see what happens in the next week and let you know. Thanks again for all your help. I hope I haven't been annoying you to much.

 

My pleasure and no you are not annoying me.

When you know something, let me know.

Ron

 

So finally I figured out something. While waiting to hear back from the manufacture who had me make the wiring diagram for the engineer to check, I decided to take the gauge apart. I knew there had to be a loose connection or just a bad resistor across the + and - current input terminals, as the engineer confirmed there should be 15Ω with the meter disconnected. So I opened it up and found the SMD resistor that went across the +- leads and checked the resistance. Well it was zero just like the terminals. So I decided to desolder it so I could check it out of the circuit. It ended up being cracked. It wasn't sitting flat on the board, kind of like it was pulled up on one end right as it was cooling or something alike. Everything else on the board looked like it was done with a machine and looked very well done. Only thing I can think is maybe it didn't pass their tests and a bad resistor was found so a tech manually desoldered it and put a new on one, just not correctly. So I looked through all my spar parts and found a 150 SMD resistor that was the same size. I tested it to make sure it was good and it read right at 15Ω, so I soldered it in place after cleaning the area from old solder real good and hoped for the best.

The next day I tried it out and it stopped tacking out like the max amps was being seen. But I still wasn't getting any readout when the motor was started. Now it just stayed at zero. I looked over the data sheet again and most of the way they showed things hooked up they had the "COM" terminal also grounded out. I hooked it up and voila! it worked! I used my fluke AC amp meter and put the primary through the reading fork on it and checked it against what the meter was saying. I remembered I was getting right around 5mA instead of 4. When I had it set at 4mA, the meter read out a few amps because it was technically seeing a 1mA increase. I messed around with the numbers a while and right at 5.12 the meter would read zero. If I went 5.11 it would show .7mA or so. Now I had the lower end right on. But having 5.12-20mA the reading was off as the amps climbed up when running no load and when load was increased. This was compared to that fluke I had setup where the primary was going through the CT. I had noted in my tests before I had saw around 12.5-13mA the CT was putting out at start-up, so I changed the 5.12-20mA to 5.12-13mA and the ratio now was pretty darn close to what the fluke was seeing up in the main control panel. It was within .2 or so mA and I figured that was close enough for what I was doing. There probably is a better way to more accurately calibrate the meter to what the CT was putting out, but im guessing it takes an expensive specialty digital current meter or something to do so.

Funny thing about the manufactures reply, they said the engineer went over my diagram (which did NOT have the "COM" grounded) and said everything was correct so they would send out a replacement. I replied back with my findings and even though the 3 year warranty could be voided I still told them what I did and that I had to ground the "com" terminal to get it to work. They replied and said that "it is absolutely necessary to connect these two points. This is required because of a bridge rectifier in the circuit of the unit. It sounds like you have the meter working as it should now. If you do have any unexpected issues with the meter, we will still honor the warranty".

So all in all everything turned out good. I thank everyone who helped me out here, especially Ron who spent allot of time dealing with my many questions. LOL.

 

Amen! Pleased it all came together and worked out for you finally.

Ron