Virginia Controls, LLC
MH-3000 User Manual, 1_03C10-VC
Page 108
10.
Controller Maintenance
WARNING: MAKE SURE THE POWER IS OFF BEFORE CONNECTING OR
DISCONNECTING ANY CONNECTORS, ADDRESS JUMPERS OR CABLES
ON THE CPU OR I/O BOARDS.
10.1
Periodic Maintenance
WARNING: Turn off the power before touching the terminals or
wiring.
Check that all wires are tight, and properly located in the terminals. Make sure no stray
stands of wire are sticking out of the terminal strips.
Check the Motor Starter contacts and Door Operator contacts (if provided) for wear.
Make sure all relays are fully seated in their sockets.
If any varistors are provided in parallel with inductive loads (such as the Valve Solenoids
or Motor Starter) check that they are physically sound. Look for signs of burn marks.
Replace it if it looks damaged.
Check the CPU battery. This can be done by cycling the power, then checking to make
sure the onboard clock is still correct. To check the time, press Nxt until the display shows
“Press ENTER to SHOW FAULT LOG”. Then press
Ent, then press
.
to show the current
time. If the date had been set, and it now shows the date as 01/01/00 then the battery is
dead. Change the battery and set the time.
Keep the controller clean and dry. Power supplies and processor chips in particular
should be keep clean of dust and other debris. Keeping the machine room itself clean will
help keep the controller clean.
10.2
Parts Replacement
10.2.1
CPU Exchange
To swap out the CPU board:
1.
Turn off the power to the controller.
2.
Note the location of all cables and wires. It is recommended that all cables and wires be
marked so that they can be returned to the correct terminal or connector, and be
oriented properly.
3.
Unplug the incoming power wiring connector from the bottom left terminal block.
4.
Unplug the duplex communication connector from the duplex connector (if used).
5.
Unplug the I/O Bus Connector.
6.
Remove the four screws holding the CPU board in place.