Refrigerating Specialties Division
1
Programmable
Liquid Level Controller
Type PLLC
For use with ITP Depth Tracker transducer
liquid level probe
Purpose:
The Programmable Liquid Level Control provides remote
liquid level management for industrial refrigeration. The
PLLC is designed for use specifically with Parker's ITP
Depth Tracker transducer liquid level probe. The PLLC
provides the power source for the current loop of the
ITP. The ITP probe is used to provide a current signal
proportional to the vertical liquid level in a standpipe or
vessel. The PLLC serving as a switching mechanism also
converts the return signal and performs up to 5 program-
mable relay functions.
Bulletin 61-50B
Type PLLC
October 2006
Installation Information
309317
Keypad Programmable Level Setting Procedure
• Supply power to the PLLC. All 4 digits will light for a
second then count down 1-4 from left to right. If there is
no level in the vessel or the probe is disconnected, the
display should read 00
• Push the "Channel" button once. The LED will display
the Channel, Mode (Relay Disposition) and the Actual
Level Set-point.
• Use the "Up" and "Down" arrow keys to select the set-
point for this level.
• Press the "Enter" key, you will hear a BEEP that will
confirm your setting.
• Channels 1, 4, and 5 are programmed using the same
procedure.
• Channel 2 is capable of operation as an additional
differential level control or it can be set to operate an
alarm function.
• Differential Level Control: Follow the same procedure
used in setting channel 3.
• Alarm: In order for Channel 2 to be used as an alarm,
a differential must be set using the High and Low level
settings of this channel.
• Push the Channel button on the keypad until Channel
2 and Mode L is displayed. Using the arrow keys, set
the low level to represent 2% of Full Scale (Full Scale =
100%) lower than the actual level setting required and
press the enter key.
• Example: If 80% is required for Channel 2 setpoint, set
the channel 2 Low setting for 78%.
• Push the channel button again to display Channel 2
and Mode H. Now set the High Level setting required
for this channel and press Enter.
• Note: 2% is the smallest value that can be en-
tered. Larger differentials can be used to allow high
liquid levels in the vessel to return to a safe operating
Wiring:
The separable terminal blocks on the PLLC will accom-
modate up to 14 gage wire. The Line Voltage Input can
be either 120/240V 60Hz or 110/220V 50Hz. The PLLC
provides the power source for the current loop of the
transducer probe. The programmable relays are indi-
vidually 5 amp fused. Relays are equipped with normally
open and closed terminals and can be wired as either.
The maximum recommended distance between PLLC and
probe is 5000 ft.
Fig.1
CHANNEL 1 HIGH RED
CHANNEL 2 LEVEL CONTROL
CHANNEL 3 LEVEL CONTROL
CHANNEL 4 LOW GREEN
CHANNEL 5 LOW RED
I S O 9 0 0 0 - 2 0 0 0 C E R T I F I E D
STRAIN RELIEF
1" CONDUIT KNOCKOUT
PLLC
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