S+S Regeltechnik AERASGARD ACO2-W Operating Instructions, Mounting & Installation page 15

G
Installation and Commissioning
Switching point setting
A potential-free changeover contact is available as a switch output.
A switching point between 10 % and 95 % of the measuring range can be selected using
the SET potentiometer. The 10 % value is added to the fresh air limit of 400 ppm for CO2.
(600...1900 ppm with MR = 0...2000 ppm or 900...4700 ppm with MR = 0...5000 ppm).
With other measurands, the corresponding lower limit is used directly as a basis.
(VOC: 10...95 %, Temperature: –23...+74 °C, Humidity: 10...95% r.H. )
The assignment of the switch output to measurand is done via DIP switch (DIP 7 and DIP 8).
Offset
Each measuring channel has a separate offset potentiometer for subsequent adjustment
of the measurement. The adjusting range is ± 10 % of the measuring range.
Display
In the first and second lines, the measurements with the corresponding units
( CO2 in ppm, VOC in %, temperature in °C, relative humidity in % r.H.)
are displayed in a cyclical series.
In the third line, the switching status of the relay is shown on the left as a circuit
●
(full = relay energised; empty
followed by the corresponding indicator
(C for CO2; V for VOC; T for temperature; H for relative humidity in % r.H.)
and the switchpoint value is shown on the right.
SUPPLY VOLTAGE :
For operating voltage reverse polarity protection, a one-way rectifier or
reverse polarity protection diode is integrated in this device variant.
This internal one-way rectifier on AC supply voltage.
The output signal is to be tapped by a measuring instrument. The output
signal is measured her against zero potential (O V) of the input voltage!
When this device is operated on DC supply voltage , the operating voltage
input UB+ is to be used for 15...36 V DC supply and UB – or GND for
ground wire!
When several devices are supplied by one 24 V AC voltage supply, it is to
be ensured that all "positive" operating voltage input terminals (+) of the
field devices are connected with each other and all "negative" operating
voltage input terminals (–) (= reference potential) are connected together
(in-phase connection of field devices). All outputs of field devices must be
referenced to the same potential!
In case of reversed polarity at one field device, a supply voltage short-
circuit would be caused by that device. The consequential short-circuit
current flowing through this field device may cause damage to it.
Therefore, pay attention to correct wiring!
○
= relay de-energised)
Connecting scheme
Power supply
AC 24V~ 0V
DC 15-36V = GND
Connecting scheme
Power supply
AC 24V~ 0V
DC 15-36V = GND
15
Individual operation
Circuitry
V
Parallel operation
Circuitry Circuitry