Bulletin 61-60
4
24V AC/DC
(50/60 Hz)
1
2
3
Controller
or
PLC
mA
Alternative (-)
Supply
Electrical Instruction
HBLT probes are supplied with a 4-pole plug, DIN 43650,
connector.
Setting of Refrigerant
The HBLT probes are factory set for ammonia (NH
3
), and water
(H
2
O). Settings for all other refrigerants or in case the electronics
has been replaced, follow the procedure below.
1. To get in the refrigeration mode setting push the calibration
push button and keep it pressed while 24 V/plug is connected
and then release the push button.
2. Release the calibration push button. Observe the present
refrigerant setting and measure the 4-20 mA output signal.
1 - flash of Green LED - output signal is ~ 5 mA = R717 or R718
(factory setting)
2 - flashes of Green LED - output signal is ~ 6 mA = R22
3 - flashes of Green LED - output signal is ~ 7 mA = R404A
4 - flashes of Green LED - output signal is ~ 8 mA = R134a
5 - flashes of Green LED - output signal is ~ 9 mA = R744
3. Activate the calibration push button to select required
refrigerant.
Each activating will cause the HBLT to step to next refrigerant
according to below sequence:
~ 5 mA = R717 or R718 (factory setting)
~ 6 mA = R22
~ 7 mA = R404A
~ 8 mA = R134a
~ 9 mA = R744
4. When the current corresponds to the required refrigerant, wait
10 seconds until the green LED is constant ON (not flashing).
This indicates that the required refrigerant has been selected.
5. To leave the setting mode isolate the voltage supply to the level
transmitter (disconnect plug from transmitter)
Go through step 1, 2 and 5 if you wish to control the setting.
Note:
This sequence must be observed. If the supply voltage is
connected before the calibration push button is activated, the
signal damping will be changed
HBLT-A1/HBLT-A1-BSP Calibration Levels
Milliamperes Vs. Level
Milliamperes
Percent Full
4
0.0
6
12.5
8
25.0
10
37.5
12
50.0
14
62.5
16
75.0
18
87.0
20
100.0
Signal Damping
Signal damping is factory set to 15 seconds. This setting can be
altered by activating the calibration switch. The setting range is 1 to
120 seconds. Settings can be made while the system is operating
Procedure:
1. Connect the supply voltage.
2. Push the calibration push button once for each second by
which you want to increase the damping.
Example:
1. push
⇒
1 sec.
120. pushes
⇒
120 sec.
2. pushes
⇒
2 sec.
121. pushes
⇒
120 sec.
10 seconds after the last push, the value will be saved in the
memory and the green LED will start flashing again. After 10
seconds, a further push will start 1-second signal damping again.
(If the damping setting is set too high, restart the procedure from
step 1).
Calibration
The HBLT probes are factory calibrated for ammonia (NH
3
), and
water (H
2
O). Calibration is required for:
■ If the default settings do not fit the maximum and minimum
calibration points provided by the factory or if the points have to
be adjusted.
Note: The chosen factory calibration setting for the maximum
point in 20 mA and minimum point is 4 mA. See
dimensional diagram for more details.
■ A refrigerant not all ready defined.
■ If the electrical head is replaced on an existing/installed probe.
Usually the minimum calibration point is chosen to be 4 mA and
the maximum calibration point to be 20 mA, but it is also possible
to calibrate the transmitter at other calibration points.
This can be useful when calibrating on a plant with no possibility
of bringing the level to the limit points.
Default factory setting is:
0% (HBLT free of liquid) output signal: 4 mA
100% (HBLT fully covered by liquid) output signal: 20 mA
The maximum/minimum levels can be set to any value.
Wiring Diagram:
DIN Connector
