ASLD2200 - Instruction Manual
9 Outputs
9.1 Analogue Output
The ASLD2200 has one analogue output that is directly proportional to the 0 to 100% digital display. Under normal
circumstances this relates to 4 mA with the sensor at the bottom of the tank and 20 mA with the sensor at the water
surface.
There is no need to make any field adjustments during commissioning. If during maintenance it is felt that the 4-20 mA
signal needs calibration this can be carried out using the 4 mA and 20 mA potentiometer adjustments.
To calibrate the analogue output connect a multimeter on the mA setting. Remove J13 and connect multimeter across
Pins 4 & 5. The ‘motor up’ and ‘motor down’ controls can then be used to force the output to 4 mA and 20 mA as
necessary.
If the ‘Up’ button is pressed at any time the 4-20 mA loop will go to 12 mA until the ‘Down’ button is pressed and the
sludge blanket is detected.
9.2 Limit Relay
The ASLD2200 is equipped with a relay that is normally open; when either the top or bottom limit is reached this
contact will close. Either or both top and bottom limits can cause this relay to activate, links A and B are used to
configure this feature.
It should be noted that the trip point is not adjustable.
Page 18 of 30
103370IM Issue 10 Date 19/03/2018
