Vaisala HMP228 - Manual (Page 16)

HMP228
Operating Manual
M210282en-A
10
when the probe is pulled
out for maintenance, cap
the hole with a capped nut;
this way, the process can
be open although the probe
is not in place capped nut
DIN 917-M22x1.5
sealing
closing valve
(ball valve)
welded sleeve
(G1/2) or tube
with thick walls
probe
Figure 2.2.4 Installing the sensor head directly in a process pipe
2.3 Signal cabling and grounding
2.3.1 Electrical connections
CH1- and CH2- are connected
together internally (X2).
DO NOT USE POWER SUPPLY
GROUND (-) AS OUTPUT
SIGNAL GROUND (X1)!
24V
Sensor connections
Current loop or
RS485 module
Ch1 Ch2
+ - nc
Tx
GND
Rx
- - + +
X1
X2
+ Ch1 - + Ch2 -
+ 24V -
Power supply
V
mA V
mA
Figure 2.3.1 Electrical connections