Vaisala HMP228 - Manual (Page 42)

HMP228
Operating Manual
M210282en-A
36
24V
Sensor connections
Current loop or
RS485 module
Ch1 Ch2
+ - nc
Tx
GND
Rx
- - + +
X15
Ch1
Ch2
+
+ -
-
X2
Figure 4.8.1.1 Location of the CH1 and CH2 test points
CH1+ CH1-
TEST POINTS
CH1+
CH1-
mA
R
L
X2
Figure 4.8.1.2 Circuit diagram of the analogue output current test
points.
4.8.1 Calibration of the analogue outputs
The analogue outputs have been calibrated at the factory and since they are
very stable, calibration of the outputs should be performed only when there is
reason to believe that their adjustments have changed.
Disconnect the security lock jumper!