Danfoss AKS 41, Техническая брошюра

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Danfoss A/S, (AC-DSL / MWA), 04 - 006
RD8AA50
→
DKRCI.PD.SC0.A1.0 / 50H009 5
Technical leaflet Liquid level transmittter, type AKS 41 / 41U
Function and
factory setting
The rod consists of two pipes - an inner pipe and
an outer pipe. The liquid will flow up between
the two pipes and by measuring the electrical
capacitance between the pipes, the length of rod
immersed in the liquid refrigerant is registered.
The signal is transmitted as a current signal
from 4 to 0 mA (4 mA when the rod does not
register liquid - and 0 mA when the entire rod is
surrounded by liquid).
Factory setting:
The rod comes factory calibrated for R717 (NH
3
),
so that it will cover 4 to 0 mA throughout the
rod’s whole measuring range.
Any disturbances in connection with the level
measurement will be damped internally.
Setting of refrigerant
R717 (NH
3
) / R718 (H
2
O)
It is not necessary to change the settings.
The factory setting can be used.
R22 / R404A / R134a / R744
Setting for the required refrigerant must be
made by following the procedure described in
next section.
NOTE!
If an alternative refrigerant other than
the listed is used, a new Min/max
calibration of the level transmitter is
required.
The setting may be carried out before the level
transmitter is mounted on the plant.
1. To give in the refrigeration mode setting push
the calibration pushbutton and keep it pressed
while 24 V a.c. is connected and then release the
pushbutton.
NOTE!
This sequence must be observed.
If the supply voltage is connected
before the calibration pushbutton is
activated, the signal damping will be
changed.
. Release the calibration pushbutton.
Observe the present refrigerant setting
and measure the 4-20 mA output signal.
1 flash of Green LED - output signal is
~ 5 mA = R717 (factory setting)
flashes of Green LED - output signal is
~ 6 mA = R
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 pushbutton to
select required refrigerant.
Each activating will cause AKS 41 / 41U to
step to next refrigerant according to below
sequence:
~ 5 mA = R717 or R718 (factory setting)
~ 6 mA = R
~ 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.
Go through step 1, and 5 if you wish to control
the setting.
A = 43 mm (1.69")
B = 30 mm (1.18")
Please observe that when used in R718, over time
a lime coating on the outer reference pipe can be
experienced. Danfoss recommend removing this
lime coating on regular basis.