HEC-Series Service Manual
ELECTRICAL CONTROLS & THEIR FUNCTIONS
10/21/01
6-7
“PLC” (Programmable Logic Controller)
Sequence Of Controller & Machine Operation
Explanation.
The HEC-Series Tube-Ice
®
machine is controlled by a PLC (Programmable Logic
Controller). The PLC controls the sequence of events and monitors the ice machine functions. The
operational sequences of the HEC-Series Tube-Ice
®
machine can be best described as a series of eight
different modes. Each mode identifies and defines a sequence of events that occur while in that mode
and thereby cause it to move to the next mode. Only one mode is active at a time. Refer to the PLC
Flow Chart (FIGURE 6-3) in this section for sequencing and various mode paths.
Start-Up Mode.
The start-up mode is a function which prevents the premature automatic starting of
the machine at the time of installation, after a power interruption, or after a safety trip. Its normal
time period is two hours.
Initiated by the following:
1. Initial power up at the time of installation
2. Power restored after a power interruption or power failure
3. After running a “Troubleshoot” mode
4. After running a “Clean” mode
5. After running a “Total Pumpdown” mode
6. Machine faults such as:
a) Cutter overload trip (manual reset)
b) Pump overload trip (manual reset)
c) High pressure cutout trip (manual reset)
d) Control circuit fuse failure (manual replacement)
e) Compressor overload trip (automatic reset) - HEC-30 & 40 only
f) Low pressure cutout trip (automatic reset)
7. If both the “Clean” and “Ice” buttons are in the “On” position (and the harvest cycle is complete).
If all safeties in the control circuit are closed, the machine will remain in the start-up mode for a
period of two hours (120 minutes) before automatically advancing to the standby mode. The start-up
mode may be bypassed at any time by pressing the “Start” button to immediately advance to the
standby mode. Make sure the compressor crankcase is warm and there is no liquid refrigerant in with
the oil before pushing the “Start” button.
Summary of Contents for HEC-10
Page 1: ...HEC SERVICE MANUAL ...
Page 95: ...HEC Series Service Manual SERVICE OPERATIONS 10 21 01 9 13 FIGURE 9 9 Cutter Water Tank Parts ...
Page 96: ...HEC Series Service Manual SERVICE OPERATIONS 10 21 01 9 14 FIGURE 9 10 Cutter Drive Parts ...
Page 97: ...HEC Series Service Manual SERVICE OPERATIONS 10 21 01 9 15 FIGURE 9 11 Cutter Parts ...
Page 106: ...HEC Series Service Manual MODEL NUMBER STRUCTURE 10 21 01 10 1 10 Model Number Structure ...
