Sigma Controls Myriad TPC LITE Instruction Manual page 21

NOTE: Elapsed times are resettable in the 'SETUP' mode and will 'ROLLOVER' to zero
after 1,000,000 hours if not reset.
Select 'NEXT' and press 'ENTER' to view pump 3 elapsed time.
MAINTENANCE AND TROUBLE SHOOTING
MAINTENANCE:
The Myriad TPC LITE 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.
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.
WARNING
 LCD display goes dim or contrast is poor. Remove power from the unit, release the 2 rear
mounting screws and slide the unit forward in its case approximately 1 inch. On the left side
of the circuit board is an adjustable potentiometer. With a small screwdriver adjust this "pot"
to alter the contrast to the desired amount. Return the unit to its normal position and secure
the rear screws.
 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 D.C. voltage on the loop. With 2
wire (4/20MA) instruments check with a D.C. voltmeter at the level instrument, by
disconnecting the level instrument from its 2 wires and measuring across these 2 wires with
a D.C. voltmeter for the presence of 24VDC.
If D.C. voltage is present, reconnect the negative wire of the supply and insert a
milliampmeter between the positive wires. The loop should provide a signal between 4 and
20 MA. If no current is present or the current exceeds 20MA consult the level instrument
supplier.
If D.C. voltage is not present check the user supplied power supply or if using the Myriad
supply measure across terminals 24VDC and A/C. If no 24VDC is present consult factory. If
24VDC is present check field wiring between the Myriad and the field device and recheck
'SCALE' functions to ensure correct setup.
 Unit appears to be functioning but does not bring on pumps or alarms. From 'MENU 2'
scroll to 'DIAG' and press enter:
.
21