Table of Contents
Advertisement
FTM 30 DR, FTM 31 DR, FTM 32 DR
5 Electrical Connection
5.1 Wiring
Two-wire AC version
Serial connection with load:
Always connect the electronic insert in series with a load (relay, miniature contact)
to the power supply!
Direct connection without a load will destroy the electronic insert (short circuit!).
Power supply:
Alternating current 19 V* ... 250 V, 50/60 Hz.
Connect an isolating switch and (quick-acting) 1.0 A fine-wire fuse next to the
separate housing. The fine-wire fuse does not protect the electronic insert from short
circuit (no-load connection).
*Power voltage:
When calculating the minimum required voltage ensure:
• The voltage across Terminals 1 and 2 of the electronic insert must be at least 19 V.
• The voltage drop across the electronic insert can be a maximum of 12 V when
closed.
• The maximum voltage is 250 V.
Switching off a load:
The load connected in series is not completely isolated from the power mains if the
electronic switch is in the "switched off" (closed) position for a level alarm.
Due to current consumption of the electronics there is still a small residual current of
up to 4 mA flowing through the load.
If the load is a relay with a very low holding current then the relay may not de-energise.
An extra load should then be connected in parallel, e.g. a resistor.
1 2
19 ... 253 V
load
1 A
L1 N
U~
Endress+Hauser
Soliphant with FEM 41
PE
5 Electrical Connection
Soliphant with
electronic insert FEM 41
Fig. 20
Wiring
Electronic insert FEM 41
for two wire AC power supply,
electronic switch
Technical data for calculating
the power required and the load
see Page 31
21
Advertisement
Table of Contents
