Bulletin 61-60
5
Adjusting the Minimum and Maximum Calibration Points
Minimum calibration:
1. Bring the liquid level to desired minimum level.
2. Press the calibration push button and keep it activated in
approximately 5 seconds, until green LED stops flashing.
3. Activate, within the next 10 seconds, the calibration push
button once
Green LED is ON in a few seconds, and then starts flashing.
Output is now 4 mA and the HBLT is in normal operation.
Maximum calibration:
1. Bring the refrigerant liquid level to desired maximum
level.
2. Press the calibration push button and keep it activated in
approximately 5 seconds, until green LED stops flashing.
3. Activate, within the next 10 seconds, the calibration push
button two times, with 1 second in between
Green LED is ON in a few seconds, and then starts flashing.
Output is now 20 mA and HBLT is in normal operation.
Note:
Maximum calibration is only required if in other refrigerants
than ammonia best possible accuracy is required alternative if
a non pre-calibrated electronic part is mounted!
Minimum calibration when minimum level must be
different from 4 mA:
1. Bring the liquid level to desired minimum level.
2. Press the calibration push button and keep it activated in
approximately 5 seconds, until green LED stops flashing.
3. Activate, within the next 10 seconds, the calibration
push button once and keep it activated. (If calibration
push button is not activated within 10 seconds, it will
automatically leave calibration mode and return to
normal operation)
4. Observe the output mA signal increasing fast starting at 4
mA.
5. Release the calibration push button when the output
signal is a approximately 0.5 mA from the desired point. 6.
All the next activations will increase the output signal by
approximately 0.05 mA
6. Approximately 10 seconds after the latest activation the
LED starts flashing
7. Output now corresponds to the value measured at the
latest activation.
Maximum calibration when maximum level must be
different from 20 mA:
1. Bring the liquid level to desired maximum level.
2. Press the calibration push button and keep it activated in
approximately 5 seconds, until green LED stops flashing.
3. Activate, within the next 10 seconds, the calibration push
button two times, with 1 second in between, and keep
it activated. (If calibration push button is not activated
within 10 seconds, it will automatically leave calibration
mode and return to normal operation)
4. Observe the output mA signal decreasing fast starting at
20 mA.
5. Release the calibration push button when the output
signal is approximately 0.5 mA from the desired point.
6. All the next activations will decrease the output signal by
approximately 0.05 mA
7. Approximately 10 seconds after the latest activation the
LED starts flashing
8. Output now corresponds to the value measured at the
latest activation.
Reset to Factory Settings
The HBLT can always be reset to factory default settings regardless
of any revised calibration values.
1. Press the calibration push button and keep it activated in min.
20 seconds, until green LED starts flashing.
2. Release the calibration push button.
3. When LED starts flashing, reset to factory setting is completed.
All probes reset to the factory setting are pre-calibrated to
ammonia with a sensor tube length of 1500 mm/59” and a signal
damping of 15 seconds. See the calibrating on site section of this
document for further instructions.
LED Indication
When voltage is applied the LED will flash rapidly as many times
as it has been calibrated through its lifetime. The current mA
output is activated as soon as the flashing sequence has changed
from rapid to slowly flashing.
Normal operation:
At normal operation the Green LED will be flashing slowly.
Generally the Green LED is ON every time calibration push button
is activated.
Calibration mode:
In calibration mode (Press the calibration push button and keep it
activated in approximately 5 seconds) the Green LED is OFF.
Change of refrigerant:
In refrigeration mode setting (Push the calibration push button
and keep it pressed while 24 V is connected and then release
the push button) the green LED is OFF until the push button is
released.
After this the green LED will flash according to the type of
refrigerant.
When the refrigerant has been selected, the green LED is
constantly ON.
