Endress+Hauser nivotester FTC 422 Montage- Und Betriebsanleitung Seite 24

Installation
Selection of fail-safe mode
Table 1
Truth table for fail-safe mode
Output circuit
Electronic insert
Fig. 6
Connection diagram:
Nivotester FTC 422 to
electronic insert EC 61 Z
24
The fail-safe mode is controlled by a bridge between terminals 12
and 13 of the Nivotester. The function can be taken from Table 1
and fig. 9 and 10, pages 30 and 31.
Nivotester Maximum
bridge 12-13
FTC 422 Relay de-energises at
maximum and remains
so until minimum is
reached.
It de-energises on
power failure.
The potential-free change-over contact can be used to control
relays, solenoid valves, contactors etc. according to the signal
received and the selected fail-safe mode. It is located at terminals
4, 5 and 6 of the Nivotester.
• If instruments with high inductance are to be connected, it is
recommended that a spark arrester is provided to protect the
relay contacts.
• The switching capacity of the relay is listed in Section 5.
Connect the Nivotester and electronic insert by a screened 3-wire
installation cable: line resistance max. 25 Ω per core.
• The screening is grounded at one end only.
Fail-safe mode:
without bridge 12-13: Min. fail-safe mode
with bridge: Max. fail-safe mode
Signal 3...12 V
NIVOTESTER
FTC 422
Bridge 1-2
Probe head
Relay
housing
output
DC
or
AC
Power
Probe
supply
Nivotester FTC 422
Minimum
no bridge 12-13
Relay de-energises at
minimum and remains
so until maximum is
reached.
It de-energises on
power failure.
Ground connection in
probe head
Electronic insert
EC 61 Z
Colour: orange