CLASS 500 ADVANCED KWH/DEMAND METER
7
62-0304—05
Fig. 7. Location of LED D5 (labeled “MTR”) and Ethernet board.
Verify that the AC MAINS voltage wires are all connected to the correct positions on terminal block TB1. Inspect the MAINS input
wiring to verify each conductor is terminated at the correct terminal block position. Using an AC voltmeter, measure the AC
voltage for each Phase to Neutral terminal and to the frame ground point.
Load each current sensor by running at least 1% of the full-scale rated current through the conductor being monitored by each
phase. For example, a 2 Amp load is required on 200 Amp rated sensors for each phase to perform sensor diagnostic
procedures.
• Verify that the current sensor white and black conductors are installed in the correct header positions.
• Verify that the current sensors are installed in the correct direction on the conductor being monitored.
• Verify that the current sensors plugs are terminated in the correct header on the Main Power board.
If the error messages still haven’t been cleared, measure the AC voltage output across the plug terminals of each current sensor
individually. Set the AC voltmeter to the 20 volt scale. If a reading of zero volts is indicated on the voltmeter, check for an open
circuit. An open could exist at the plug terminals or at a splicing junction. Also verify that the core halves are assembled tightly.
Final Main Power Board Checks
Once the phase error has been corrected, the display LCD “Check Sensor” error should extinguish and the main power board
LED D5 should flash at a rate of once per second. Also verify that LED D4, labeled “CPU”, is flashing at a rate of once per second
and synchronously with LED D5.
D5
ETHERNET
BOARD
M28748A