Vogt HEC-10, Service Manual

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HEC-Series Service Manual
ELECTRICAL CONTROLS & THEIR FUNCTIONS
10/21/01
6-5
PLC Features & Functions
(Condensed Description)
The PLC provides many beneficial features as follows:
1. Identifies machines faults and stores the identity of the last fault.
2. Automated total pump down prior to a clean mode.
3. Performs partial pump down when machine cycles off by “Bin Stat” or “Ice” switch.
4. Provides fault identification:
a. Short cycle fault
b. Long freeze cycle fault
c. High/low pressure fault during freeze
d. High/low pressure fault during thaw
e. High/low pressure fault during partial pump down
f. High/low pressure fault during total pump down
5. Automatic (2-hour delayed) restart after being off from:
a. Power failure
b. Power interruption
c. Compressor overload cutout
d. Low pressure fault
e. Long freeze fault
f. Short cycle fault
6. Built in adjustable thaw timer (range 1 1/2-5 minutes).
7. Closes “A” (liquid feed) solenoid valve and stops the water pump seven seconds before the
harvest begins providing a slight pump out of the freezer and accumulator and allowing the water
level to stabilize before the cutter turns.
8. Sequences the machine functions to assure the highest product capacity with the least amount of
personal attention.