Samson 3738-20, Mounting And Operating Instructions

Page: 12 / 84

12 EB 8390 EN
Design and principle of operation
NAMUR contacts A, B, C
The contacts can be configured as either NO
or NC contacts. See Fig. 4 and section 8.5.
NAMUR contact St
This contact is a NC contact.
3.1 Versions
Type 3738-20-xxx1400xxx000 Electronic
Limit Switch with integrated solenoid valve
The electronic limit switch with integrated so-
lenoid valve form a compact unit together
with a pneumatic actuator, which is easy to
mount. The 3/2-way or 5/2-way function of
the solenoid valve is selected by changing
the position of a molded seal.
Based on VDI/VDE 3845, level 2, its version
can be mounted onto Pfeiffer Type 31b Rota -
ry Actuators. The need for additional pneu-
matic connections is eliminated.
Type 3738-20-xxx1000xxxx00 Electronic
Limit Switch for external solenoid valve
The electronic limit switch for an external so-
lenoid valve allows switching capacities up
to max. 18 W at 24 V DC, meaning all
common solenoid valves, even the Ex e ver-
sions, can be combined with the electronic
limit switch. This version is suitable for rotary
actuators according to VDI/VDE 3845, lev -
el 1. See Fig. 4.
Changes to the electronic limit switch's set-
tings do not effect the external solenoid
valve.
NC contact NO contact
No response Response
Response No response
Wire break Wire break
[mA] [mA]
2.1
1.2
0.05
2.1
1.2
0.05
Fig. 4: NO and NC contacts