Flowline LC52 DataPoint - Manual (Page 5)

Automatic Fill:
This system consists of a tank with a valve controller by the LC52. At
a low set point, the valve opens, filling the tank, At the high set point,
the valve closes. Part of a proper fail-safe design for this particular
system is that if power is lost to
the controller for any reason, the
valve filling the tank must close.
Therefore, we connect the valve
to the NO side of the relay. When
the relay is energized, the valve
will open and fill the tank. The
relay indicator will correspond
directly to the Open/Close status
of the valve.
NOTE: If the device’s load exceeds the rating of the controller’s
relay, a stepper relay of higher capacity must be used as part of the
system design.
Determining the settings of LATCH and INVERT
This is the way the system must operate:
• When the liquid level is below the low set point, the valve should
open, starting to fill the tank.
• When the liquid is above the low set point, the valve will remain
open.
• When the liquid reaches the high set point, the valve should
close.
Latch: In any two-sensor control system, LATCH must be ON.
Invert: Referring to the logic chart in Step One, we look for the set-
ting that will de-energize the relay (valve close) when both inputs are
ON (High level reached). In this system, Invert should be ON.
Automatic Empty:
In the same manner, the controller can be used to automatically empty
a tank with just a change to the setting of the INVERT switch.
• The valve is still connected to the NO side of the relay to allow
for a power failure fail-safe condition.
• The normal state of the valve is closed. In this state, we want the
relay to be energized at the high set point (opening valve to drain
tank). The relay will de-energize at the low set point (closing
valve).
Note: A fail-safe design is important. If the tank is being passively
filled, and a valve must be used to actively empty it, a power failure
to either the controller or the pump circuits will cause overflow.
Step Six Step Seven
INSTALLATION INSTALLATION
Relay Input Wiring:
The single pole, double throw isolated relay is
rated 250 VAC, 10 A, 1/2 Hp. The two terminals
marked Normally Open (NO) and Normally
Closed (NC) will be used in different applications.
Note: The “Normal” state is when the relay’s coil
is de-energized and the Red relay LED is Off.
Low-Level Alarm:
The goal is to make sure that the liquid level does not fall below a
certain point. If it does, an alarm is supposed to sound, alerting the
operator of a low-level condition.
If power is accidentally cut to the
controller, the sensor’s ability to
warn the operator of a low-level
condition could be lost. The sys-
tem must alert the operator not
only to low fluid level, but to con-
troller power loss.
To do this, connect the hot lead of
the alarm to the NC side of the
relay terminal of the LC52. If
power is lost, the relay will be de-energized, and the alarm will sound
(if there is still power to the alarm circuit itself). The alarm circuit
should have a non-interruptible power supply or some other indicator
or backup alarm to warn of a power failure in the alarm circuit.
In this application, the normal status of the sensor at the bottom of the
tank will be wet, and the relay will be energized holding the alarm
circuit open. Both the red relay LED and amber input LED will be on
simultaneously, so for this application, INVERT should be set to the
OFF position.
High Level Alarm:
In the same manner, the controller can be used to sound an alarm
when fluid reaches a high level, with just a change in the location of
the sensor and the setting of the INVERT switch.
• The alarm is still connected to the NC side of the relay to allow
for a power failure alarm.
• The sensor is normally dry. In this dry condition, we want the relay
to be energized so the alarm does not sound: i.e., the red relay LED
should be on whenever the amber sensor LED is off. So we turn
INVERT ON. If the fluid level rises to the high sensor point, the
sensor goes on, the relay de-energizes, and the alarm sounds.
VAC Power Input Wiring:
Observe the POWER SUPPLY label on the LC52.
The label identifies the power requirement (120 or
240 VAC) and the terminal wiring. Note: Polarity
does not matter with the AC input terminal.
POWER SUPPLY
120 VAC, 50 - 60 Hz
240 VAC, 50 - 60 Hz
L1 L2 GND
NO NC
RELAY OUTPUT
250 VAC, 10A
C
RELAY 1 P O W E R
INVERT
DELAY
ON OFF
LATCH
Ground
Neutral
Hot
RELAY 1 P O W E R
INVERT
DELAY
ON OFF
LATCH
Ground
Neutral
Hot
RELAY 1 RELAY 2 P O W E R
INVERT
DELAY
INVERT
DELAY
ON OFF
LATCH
RELAY 1 RELAY 2
P O W E R
INVERT
DELAY
INVERT
DELAY
ON OFF
LATCH