27
NT935-4
SERIES
1.
Cable 20 x AWG 20/19 Cu/Sn
2.
Section 0.55 mm²
3.
Flame retardant insulation PVC105
4.
CEI 20.35 IEC 332.1 regulations
5.
Maximum operating temperature: 90°C
6.
Conformation: 4 sets of three twisted and coloured conductors
7.
Shield in Cu/Sn
8.
Flame retardant PVC sheath
9.
External diameter 12mm
10.
Standard conformation in 100m coils
Pt100 EXTENSION CABLE TECHNICAL SPECIFICATIONS
OUTPUT 4.20mA
It is possible to connect a displaying or acquisition device to the 4.20 mA output.
The permitted load impedance for output is from 0 to 500 ohm.
The loop is optically isolated to guarantee the maximum immunity to interference.
The 4-20 mA signal is referred to the 0-240°C range with an accuracy of 1% of full scale value
The output can be programmed in the following modes:
1-2-3-4:
the 4.20 mA output refers to the fixed channel that has been set.
SCAN:
the 4.20 mA output automatically scans the active channels every 2 seconds
HOT:
the 4.20mA output automatically refers to the hottest channel among the active ones (default setting)
See steps 39 - 40 of the table on page 15.
Note: if the 4.20 output is programmed on channel and it is disabled, the control unit will automatically set on
HOT.
The current-temperature ratio varies according to the device temperature range:
For the range 0°C + 240°C the ratio is: I
out
= (T/15)+4 (T=temperature in °C)
For the range
–40°C + 200°C the ratio is: I
out
= (T/15)+6.7 (T=temperature in °C)
Example: range 0°C + 240°C:
If T=100°C
I
out
= 100/15+4= 10.67 mA (±0.2 mA)
Note: We recommend you use a screened and twisted cable; connect the twisted pair taking polarities into account and
lay the network avoiding narrow bends or ring windings. Always position the twisted pair far from power cables.
ONLY FOR NT935-4 AD
The NT935-4 has n.o selection (contact open ) / n.c (normally closed contact) for ALARM, TRIP and FAULT relays,
programming steps 26 to 31 page 15. The selection of the setting YES/NO introduces functions Fail Safe and No Fail
Safe.
ALARM AND TRIP
Setting NO (NO Fail safe) normally open contacts are in positions 5-7 Alarm and 8-10 Trip, they switch only when limits
are reached preset temperature.
Setting YES (Fail Safe) normally closed contacts are in positions 5-7 Alarm and 8-10 Trip, they switch only when limits
are reached preset temperature.
FAULT
Setting YES (Fail safe) the contact 11-12 is positioned as normally open, switches (closed) when a fault condition is
identified; see section on page 13 alarms and ventilation.
Setting NO (NO Fail safe) the contact 11-12 is positioned as normally closed, switches (open) when a fault condition is
identified; see section on page 13 alarms and ventilation.
Disabling the failsafe function on the fault contact the unit will no longer be able to report the fault for lack of power. In
this case it is suggested that the enabling of the fail safe on the ALARM contact for the above indication.
NOTE: When the unit is located in one of the methods described below does not monitor heat, also the relay will all be
banned,
the FAULT led start blinking.
Vis. display programming.
PRG programming.
Test of the relays.
The FAIL SAFE is temporarily disabled The FAULT relay switches.
FAIL SAFE FUNCTION
