Danfoss AKS 41 Liquid Level Transmitter
Section 9
Publication 9-45
Issue 1 : 10/11
Page 9 of 18
(e)
Remove the meter from the DIN plug and reassemble.
(f)
Leave setting mode by removing the DIN plug so there is no
voltage to the level transmitter. After a few seconds, refit the plug.
The level transmitter should now operate normally.
(g)
For refrigerants other than R717 and R718, it is recommended to
check the minimum and maximum liquid level calibration
approximately 7 days after operation commences; refer to 6.2.
6.2.
Calibration for Minimum and Maximum Liquid Level
Calibrating the transmitter sets the two outer limits of the measuring
range, i.e. the point on the capacitance rod where the output signal is to
be 4 mA and the point where the signal is to be 20 mA; refer to Fig 5.
Fig 5 Calibration for Minimum and Maximum Liquid Level
The active measuring range starts 30 mm from the bottom of the rod and
ends 43 mm from the top (gasket’s contact face). The liquid level
transmitter has been factory-calibrated to R717 (ammonia), so that the
entire measuring range is utilised, i.e. the transmitter’s output signal is
4 mA when the rod is out of the liquid and 20 mA when the liquid is
43 mm from the top of the rod.
If the transmitter is to be used with R22, R404a, R134a or R744 there is
no need to calibrate, simply set to the refrigerant used; refer to 6.1.
It is usually necessary to calibrate the AKS 41/AKS 41U if:
•
The AKS 41/AKS 41U is used with a refrigerant other than
those listed in Table 1.
•
The insertion length does not correspond with the refrigerant
measured level range.
•
The transmitter housing assembly is replaced.
Calibration for minimum liquid level can be carried out without calibrating
for maximum liquid level at the same time. However, if one level is
changed on its own the other level will automatically move by the same
distance. For example, if the new calibration for minimum liquid level is
10 mm further down the rod, the maximum liquid level moves down by
the same amount.
(mA) Output Signal
