Having trouble with JLD 404 DC power meter

[lordwacky]

Hello,

I'm having trouble with the JLD 404 DC power meter. I'm using this meter to monitor the voltage,current and power usage from a battery pack powering a DC motor with a PWM speed controller. This is a high current application, upto 1000A. For this system have the shunt located on the negative leg between the negative battery terminal and the PWM speed controller. Since my system can go up to 1000A I am using two 500A 75mv shunts in parallel. The positive battery terminal is connected to pin 5 on the meter. The "positive" side of the shunt is connected to pin 9 and the negative side of the shunt and the negative battery terminal are connected to pin 10. The Meter is being powered by an isolated 12V power source.

The problem I am having is the current reading is completely wrong. I have compared the reading on the power meter to to a handheld clamp meter and another Hall effect current sensor and the current being reported by the power meter is completely wrong. The clamp meter and halleffect meter will measure 10-20A during the test while the power meter is measuring in the hundreds and is very erradic. In addition the current measurement is reported as a negative number. I have tried to reverse the leads on the shunt and the reading remains negative.

I am not sure what the problem is. I have changed multiple different programming setting in the meter and none seem to have fixed the issue. Can you please provide me with assistance?

thank you

[Tech_Marco]

Pay attention to two issues:
1) Frequency - this is a DC power meter but PWM isn't really a pure 'DC' and the frequency could cause an issue. You may need to turn on 'digital fitration' to slow down the response

2) Make sure that the main power wire going to the shunt before the meter. Do not 'Y' the main power and the shunt righ on the meter's terminals as doing so, you will not get correct reading.