Electronic insert
The Nivotester and electronic insert are connected by a screened
3-wire installation cable: two wires supply direct current to the
insert, the third carries a voltage signal (3...12V) proportional to the
capacitance of the probe back to the transmitter.
Fig. 6 shows the connection of the probe to the Nivotester.
•
The probe is grounded to terminal 6 of the electronic insert.
•
Ground the screening at one end only.
Output circuit
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 as follows:
•
max. 250 V a.c., max. 6 A, max 1500 VA at cos
ϕ
= 1,
max. 750 VA at cos
ϕ ≥
0.7.
•
max. 250 V d.c., max. 6 A, max. 200 W.
•
response time 0.2 s, for FTC 421 adjustable 0.5 ... 20 s.
•
short-out time on power failure approx. 0.3 s.
Fail-safe mode:
without bridge 12-13: Min. fail-safe mode
with bridge: Max. fail-safe mode
Signal 3
…
12 V
NIVOTESTER
FTC 420/421
Power
supply
Relay
output
Bridge 1-2 only if
conductive
deposit on probe
Probe head
housing
Probe
Electronic insert
EC 61 Z
Colour: Orange
Ground connection in
probe head
Fig. 6
Connection diagram:
Nivotester FTC 420/421 to
electronic insert EC 61 Z
Installation
27
