TEMPERATURE DIAGNOSTICS
When one of the temperature sensors senses a temperature 1°C higher than the alarm threshold, 5 seconds later the
ALARM relay switches and the ALARM LED of the affected channel (CHn) lights up.
When the trip temperature limit is exceeded, the TRIP relay switches and the TRIP LED of the affected channel (CHn)
lights up.
As soon as the recorded temperature returns to values equal to or lower than the limit set for the ALARM and TRIP relays
switching, these relays de-energise and the corresponding LEDs switch off.
The ALARM and TRIP values are kept in the internal memory: they can be recalled by entering the Vis modes
(programmed parameter display) and modified in PRG (programming) mode.
COOLING FAN CONTROL
The unit NT935-4 has two contacts FAN (FAN1 and FAN2), if properly programmed, can control ON-OFF of fans for
cooling system checked.
The high flexibility of the NT935-4 allows you to select, for each channel, an operation mode for contact management of
FAN1 and FAN2. During the programming of the individual channel, enabled, you will be asked to select one of the
following ways to activate FAN, dedicated to that channel:
YES: FAN1 + FAN2 enabled flashing
The selected channel CHn, enable the switching of both contacts FAN1 and FAN2 in relation to thresholds ON - OFF
programmed for FAN1 and FAN2.
YES only FAN1 enabled flashing
The selected channel, CHn, enable the switching of the contact FAN1 in relation to the threshold ON - OFF programmed
to FAN1.
YES only FAN2 enabled flashing
The selected channel, CHn, enable the switching of the contact FAN2 in relation to the threshold ON - OFF programmed
to FAN2.
NO: FAN1 + FAN2 disable flashing
The FAN function on the selected channel, CHn, is disabled. The selected channel is not associated with any threshold
FAN.
The thresholds FAN1: (ON – OFF) and FAN2: (ON – OFF) are common to all channels CHn enabled, programmable to
step 12-19 programming page 14.
FAN1: (eg. At 70 ° C ON - OFF at 60 ° C)
FAN2: (eg. At 45 ° C ON - OFF at 35 ° C)
The values of ON and OFF can be programmed depending on the range of the device, FAN ON must always be greater
by at least 1 ° C since FAN OFF (recommended Δ FAN (POWER ON-OFF) + 10 ° C.
The FAN 1 / FAN 2 LED light up when the temperature exceeds 1°C the FAN ON threshold, the corresponding relay
switches, and turns off when the temperature goes below 1°C the FAN OFF threshold, the corresponding relay switches.
FAN TEST
By programming (HFn), it is possible to have the fans operating 5 minutes every "xxx" hours, regardless of the column or
ambient temperature values (i.e.: with HFn=001 the fans are activated for 5 minutes every hour).
This function aims at verifying the fan operation and their control apparatus periodically.
By setting NO this function is inhibited.
To enable the Hfn function, read the programming section on pages 14-15.
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