Service & Support
Maintenance and Troubleshooting
1. Potential problem:
The display is blank after applying electric power to the power meter.
Possible cause:
The meter may not be receiving the necessary power.
Possible solution:
(1) Use the multimeter to measure if there is required work voltage on the terminals 1 and 2 of the auxiliary power supply.
(2) Check if the terminal connections of auxiliary power supply are reliable.

2. Potential problem:
The meter flashes abnormally after electrified.
Possible cause:
The voltage supplied exceeds the working range.
Possible solution:
(1) Break the auxiliary power supply.
(2) Inspect if the electric power supplied is beyond the range marked on meter.
(3) Inspect if the input signal exceeds 120% of rated value.
(4) Inspect if the ambient temperature exceeds the upper limit of appropriate working temperature.
(5) Electrify the meter again.

3. Potential problem:
The meter displays garbles after electrified.
Possible cause:
The meter is interfered a lot.
Possible solution:
Firstly break the auxiliary power supply, and then electrify the meter again.

4. Potential problem:
The data displayed is inaccurate.
Possible cause:
(1) The transmitting ratio of the transformer is inaccurate.
(2) The parameters supplied are not matched.
Possible solution:
(1) Check if the transmitting ratios set in meter are in accordance with those of PT or CT.
(2) Check if the rated values of voltage and current are accordant.

5. Potential problem:
The meter has no response to the signals.
Possible cause:
The meter may not be receiving the signals.
Possible solution:
Check if there are reliable signals between wiring terminals of meter.

6. Potential problem:
Phase loss for 3-phase meter
Possible cause:
(1) The meter may not be receiving the signals.
(2) The settings are not matched.
Possible solution:
(1) Check if there are signals between the wiring terminals of meter.
(2) Check if the terminal connections are reliable.
(3) Judge it is the problem of meter or problem of external circuit by connecting the signal wire of normally displayed phase to the terminal of phase loss.
(4) Check if the practical wiring method is in compliance with that set in meter.

7. Potential problem:
The energy metering is inaccurate.
Possible cause:
(1) The transmitting ratio is not correct.
(2) The phase sequence of voltage or current is not correct.
Possible solution:
(1) Check if the transmitting ratio set in the meter is in accordance with that of PT/CT.
(2) Check if the phase sequence of voltage or current is accurate.
(3) When the meter which can display power value is electrified, check whether the single-phase power has negative sign indication, which can possibly show that the in/out wire of current for corresponding phase is connected reversely.

8. Potential problem:
Wrong analog output
Possible cause:
The measuring range or item correspondence of analog output is not accurate.
Possible solution:
(1) Verify the upper/lower limit correspondence of analog output measuring range.
(2) Check if the corresponding electrical variables of analog output is correct, such as U, I, P, Q, etc.
(3) Ensure the inspection equipments work normally.
(4) If using PLC, ensure the wiring setting of PLC analog input is correct.

9. Potential problem:
The communication function is abnormal.
(1) The meter doesn’t send back data.
Possible solution:
First ensure the communication settings of meter, such as, slave address, baud rate, check mode, etc. are in compliance with that of host equipment. In case more than one meter doesn’t send back the data, please check if the connection of communication bus on site is correct, and if the RS485 converter is running regularly.
In case only one or a few of meters communicate abnormally, the communication wiring should also be checked, through exchanging the slave addresses of regular and irregular meters to exclude or verify the software fault of host unit, or exchanging the installation position of regular and irregular meters to exclude or verify the meter fault.
(2) The meter sends back incorrect data.
Possible solution:
The communication data of meter include primary data (float) and secondary data (int/long). Please read carefully the description about storing address and storing format of data in the communication address table, and ensure converting in accordance with proper data format.
The communication of meter can be tested by ModScan32 software which follows standard Modbus-RTU protocol. Besides, the data got from the test can be displayed in integer, floating point or hexadecimal numbers, and can be compared directly with the data displayed on the meter.
(3) State information of communication indication signal
Possible solution:
In the process of communication test, when the meter receives data, the communication indication signal on the display screen of meter will flash.

10. Potential problem:
After electrified, the running indication light of main body of motor protection controller is constantly on, but the display module works abnormally.
Possible cause:
Poor contact of the DB9 line used to connect the main body with the display module (or disconnection after bending).
Possible solution:
Cut the electricity, and then tighten the DB9 connection line, or change another DB9.

11. Potential problem:
The contactor works abnormally when the test control loop is without load.
Providing the debugging control loop has no load, when the controller receives start command via the display module buttons or the DI terminal, the contactor, with electricity, will be released after 2-second closing, namely, cannot keep closing state. At the same time, the corresponding display module will show “start” progress bar for 2 seconds, and then return to “ready to start” page. Also, the relay may work abnormally.
Possible cause:
Under all control modes except “protection mode”, the controller will judge it starts normally via inspecting the main-loop current. When receiving start command, the main relay controlling the contactor loop is closed, and then the contactor is closed after electrified. If after 2 seconds, the current of main loop doesn’t reach over 10% of rated current, the motor is assumed to not work, then the relay will be open, and the contactor becomes released without electricity as a result.
Possible solution:
(1) When conducting calibration without load, enter the parameter setting page. Under controller parameter setting->run mode, modify “run” into “test”. After modification, the controller will not track the main loop current, and all protection functions will not work, but the control logic works normally. At this time, you can check whether the control loop without load is normal or not. After calibration, please change the mode into “run”.
(2) Calibration with load

12. Potential problem:
The motor works normally, but the parameters measured are not correct. The motor protection controller may run abnormally or not run at all. In the display module’s “run data” page may show as follows: three phases of current are all 0%; two phases of current are normal, but the other is 0%; three phases of current are not displaying 0, but the values are far different from the practical values; the voltage and current values are correct, but the power and power factor values are wrong.
Possible cause:
(1) The plug of controller’s self-contained transformer may not connect well with the controller main body.
(2) The rated current or CT transmitting ratio of current is set incorrectly.
(3) The current specification of controller is not in compliance with that of motor loop.
(4) The phase sequence of voltage or current is not correct.
Possible solution:
(1) Check if the transformer connects well with the controller.
(2) Appropriately set the rated current and CT transformer ratio (if any external transformer is connected) of the motor.
(3) Check the phase sequence of voltage or current.