40
Planning
2596995_0_EN_1905
Nortec RS
4.4.1 Control Signal Input
4.4.1.1 Analog Control Signals
The Nortec RS humidifier can be regulated using up to two modulating analog input signals, and multiple
On/Off input signals for each steam cylinder. Analog controls can be supplied by Condair or by others.
The Nortec RS humidifier can be factory-configured to enable/disable modulating and On/Off control
signals, and set the signal range (refer to
). The unit can also be field-configured using the touch-
screen display.
Table 14: Nortec RS Acceptable Analog Control Signals
Control Type
Control Signal Type
Acceptable Signal
Modulating control and high limit
signals
Demand or transducer
0-5 V, 0-10 V, 1-5 V, 2-10 V, 0-20 V,
0-16 V, 3.2-16 V, 0-20 mA, 4-20 mA
On/Off control and high limit signals
On/Off
Dry contact, 24 VAC or 10 VDC
Security loop
Dry contact, 24 VAC
Nortec RS 90 RS130 and RS 180 humidifiers with dual steam cylinders have two low voltage terminal
strips (designated "A" and "B") to supply separate sets of control signals to each steam cylinder, so the
unit can be operated in series or parallel mode, as described in
"General Description" on page 1
.
All control signal wiring must use a minimum of 18 AWG, and the cable length should be kept as
short as possible.
Modulating Control
The Nortec RS humidifier can be operated with one or two modulating analog input signals per steam
cylinder. If two modulating input signals are used, both signals must be of the same type: demand signals
from an external controller, or transducer (RH sensor) signals from an external humidity sensor. In both
cases, the humidifier will not start steam production until the calculated system demand exceeds 3%.
Demand Signals:
If the humidifier receives a demand signal, it calculates the desired steam production
level (as a percentage of the total humidifier capacity) proportional to the incoming demand signal (as a
percentage of the signal range). When two demand signal inputs are used, the humidifier responds to
the lowest of the two demand signals.
Transducer Signals:
If modulating transducers (RH sensor) are used, the humidifier uses an internal
PI (proportional-integral) controller to calculate system demand for each channel input. The calculated
system demand value for each input channel will vary depending upon the configurable humidity set-
points, as well as proportional and integral functions of the internal controller. If two transducer signals
are used, two system demand values are calculated and the humidifier responds to the lowest of the two
calculated values. Transducers with a possible zero input are not recommended. The Nortec RS humidi-
fier also supports an optional low and high humidity alarm warning with re-configurable humidity triggers.
Security Loop
The security loop connected between Pin 1 and Pin 2 on the low voltage terminal strip consists of 24 VAC
On/Off input devices that are part of the humidification system. The Nortec RS humidifier will not oper-
ate unless this circuit is closed. The security loop also allows On/Off control of the humidifier, and can
be used as feedback to indicate the functional status of the humidification system components critical
to the proper and safe operation of the humidifier.
