13
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DISPLAY REMAINS AT ZERO OR SHOWS NO CHANGE -- If the display remains at zero or
shows no change but the process is changing, check for DC voltage on the loop. With 2 wire (4/20MA)
instruments check with a DC voltmeter at the level instrument, by disconnecting the level instrument
from its 2 wires and measuring across these 2 wires with a DC voltmeter for the presence of 24VDC.
Check the diagnostic screen for analog input value.
If DC voltage is present, reconnect the negative wire of the supply and insert a milliamp meter between
the positive wires. The loop should provide a signal between 4 and 20 MA. If no current is present
or & current exceeds 20MA consult the level instrument supplier.
If DC voltage is not present check the user supplied power supply or if using the 700 DPCF/TPCF supply
measure across terminals 24VDC and + and -. If no 24VDC is present consult factory. If 24VDC is
present check field wiring between the 700 DPC and the field device and recheck ‘SCALE’ functions to
ensure correct setup.
NOTE: This should be done by using the user provided circuit breaker or fuse,
not by removing the power wires at the terminal block. Serious injury or death
can occur if contact is made with the incoming AC power.
MAINTENANCE AND TROUBLE SHOOTING
The Series 700 MM is a digital solid state device which requires no periodic maintenance.
Occasional checks of the unit should be carried out for physical and mechanical security of mounting,
terminal blocks, and electrical wiring.
TROUBLE SHOOTING
•
UNIT ‘LOCKS UP’ -- Recycle power to the unit by removing AC power, waiting 10 seconds and
reconnecting power.
Summary of Contents for 700 MM
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