Vogt VT Series - PLC (Programmable Logic Controller)

Vogt
®
VT Service Manual 8-5
Service Operations
PLC (Programmable Logic Controller).
The VT-Series 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 VT-Series ice machine can be described best as a series of six
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.
FIGURE 8-5
PLC (Programmable Logic Controller)
# Description # Description
Inputs 0
Current Sensing Relay (chopper)
Outputs
0
Fault Indicator light
1
“On” Selector Switch/Bin Control
1
Liquid Feed Solenoid (R404A machines only)
2
HH Pressure Switch
2
Compressor
3
Manual Harvest (Start) Button
3
N/A
4
Clean Switch
4
Water Pump
5
High Pressure Safety Switch
5
Chopper/Hot Gas Valve/Defrost Loop valve or
6
Low Pressure Safety Switch
Suction Stop Valve (VT80 & VT100)
7
Oil Press Safety /Comp Motor OL
TABLE 8-1
PLC Inputs/Outputs
Freeze cycle Timer (PLC analog pot)
Turn Clockwise to increase freeze time
Minimum Freeze Time = 5 min
Maximum Freeze Time = 8.5 min