HB Products HBLT-A1 Liquid Level Transmitters
Section 9
Publication 9-86
Issue 1 : 10/22
Page 9 of 10
(e) Starting at 4 mA, observe the output signal increasing. Release
the pushbutton when the output signal is approximately 0.5 mA
from the desired point.
(f)
Repeat steps (c) and (d). Each repeat will increase the output
signal by approximately 0.05 mA.
10 seconds after the last repeat the green LED starts to
flash. The output now corresponds to the last measured
value and the level transmitter is in normal operation.
6.3.1.4. Maximum Calibration When the Maximum Liquid Level is Different
From 20 mA
(a) Arrange to measure the 4 to 20 mA output signal.
(b) Raise the liquid level in the vessel to the desired maximum level.
(c)
Press and hold the calibration pushbutton for approximately 5
seconds until the green LED stops flashing. Release the
pushbutton.
(d) Within the next 10 seconds press and release the pushbutton then
after 1 second press again and keep the button pressed.
NOTE: The level switch will return to normal operation if
the pushbutton is not pressed twice within 10 seconds.
(e) Starting at 20 mA, observe the output signal decreasing. Release
the pushbutton when the output signal is approximately 0.5 mA
from the desired point.
(f)
Repeat steps (c) and (d). Each repeat will decrease the output
signal by approximately 0.05 mA.
10 seconds after the last repeat the green LED starts to
flash. The output now corresponds to the last measured
value and the level transmitter is in normal operation.
6.4.
Restore Factory Default Settings
Press and hold the calibration pushbutton for ≥20 seconds, until the
green LED starts flashing indicating that the factory reset is complete.
Release the pushbutton.
The default setting is for use with R717 (ammonia) refrigerant and a
transmitter rod length of 1500 mm (59”), change if required; refer to 7.1 to
7.4.
6.5.
LED Indication
When power is applied to the level transmitter the LED will flash rapidly
as many times as the transmitter has been calibrated during its lifetime.
The 4 to 20 mA output signal is recognised and updated as soon as the
flashing changes from rapid to slow flashing.
Normal Operation
The green LED flashes slowly during normal operation. Generally, the
green LED is lit when the calibration pushbutton is pressed.
Selecting the Refrigerant
Refer to 6.1.
The green LED is unlit until the pushbutton is released at the end of step
(b). The LED then flashes a number of times according to the refrigerant,
then remains lit when the refrigerant has been selected.
Calibration
Refer to 6.3.
While calibration is taking place during step (b) the green LED is unlit.
