SAE-1011
SAE-1012
Room Carbon Dioxide Transmitter
Installation Instructions
INTRODUCTION
The room CO₂ transmitter device uses a highly accurate and reliable non-
dispersive infrared (NDIR) sensor in an attractive, low profile enclosure for
room applications to monitor CO₂ levels. The sensor uses dual channel optics
and LTA (long term adjustment) signal processing technology to deliver
industry leading long-term accuracy and reliability. These technology features
ensure optimum measurement stability for both periodic and constant occupancy
applications, so the device is equally suitable for the classroom or the
hospital room. Standard features include a field selectable output signal of
either 4-20 mA, 0-5 Vdc or 0-10 Vdc for the highest versatility, programmable
CO₂ measurement span, a backlit alpha-numeric LCD and easy menu operation for
configuration. Optional features include a resistive temperature sensor output
(with LCD display of temperature in either °C or °F), a control relay with
programmable setpoint, hysteresis and time delay, an up/down setpoint control
with various resistive output ranges and a dry-contact override switch.
BEFORE INSTALLATION
Read these instructions carefully before installing and commissioning the
device. Failure to follow these instructions may result in product damage. Do
not use in an explosive or hazardous environment, with combustible or
flammable gases, as a safety or emergency stop device or in any other
application where failure of the product could result in personal injury. Take
electrostatic discharge precautions during installation. De-energize the power
supply prior to installation, this device is intended for indoor air
conditioned spaces, contact factory or other applications. Do not exceed
device ratings. This product is not intended for life-safety applications.
NOTE: This CO₂ sensor incorporates a Self Calibration feature to correct
CO₂, sensor drift. This feature is recommended for applications where the W2
will be exposed to fresh air (400 ppm) at least one hour per day. If the
monitored space is occupied 24 hours or consistently maintains higher or lower
levels of CO₂ , it is recommended that this feature be turned off, but yearly
calibration will be required. If the self calibration is disabled at
installation time without allowing for 7 day auto calibration cycle, then a
manual calibration should be performed to ensure accuracy of the device.
MOUNTING
The transmitter installs directly on a standard electrical box and should be
mounted five feet from the floor of the area to be controlled. Do not mount
the sensor near doors, opening windows, supply air diffusers or other known
disturbances. Avoid areas where the detector is exposed to vibrations or rapid
temperature changes. Prevent measurement errors by sealing the wall or conduit
openings to prevent air migration from the wall cavity. The cover is hooked to
the base at the top edge and must be removed from the bottom edge first. Use a
small Phillips screwdriver to loosen the security screw as shown in Figure 1.
Complete removal of the screw is not required. Use the screwdriver to
carefully pry each bottom corner if necessary. Tip the cover away from the
base and sit it aside as shown in Figure 2.
The PCB must be removed from the base to access the mounting holes. Follow
anti-static procedures when handling the PCB and be careful not to touch the
sensors.
The PCB is removed by pressing the enclosure base to unsnap the latch near the
bottom edge, then the PCB can be lifted out of the base as shown in Figure 3.
Sit the PCB aside until the base is mounted on the wall. For added protection,
place the PCB in the supplied anti-static bag.
Mount the base by screwing to an electrical box or directly to the wall as
shown in Figure 4.
After the base is screwed to an electrical box or directly to the wall using
the appropriate holes, remove the PCB from the anti-static bag, feed
connection wires through the center hole and place the top of the PCB into the
PCB holders on the backplate and snap the bottom of the PCB into place as
shown in Figure 4.
Making wiring connections as per the Wiring Illustrations on page 2 and
install the decorative cover by placing the top of the cover into the cover
holder on the top of the backplate and snapping the bottom into place as shown
in Figure 4. Tighten the security screw with a Phillips screwdriver.
WIRING
Deactivate the power supply until all connections are made to the device to
prevent electrical shock or equipment damage. Use 16-22 AWG shielded wire for
all connections (only ground the shield at the controller end) and do not
locate the device wires in the same conduit with wiring used to supply
inductive loads such as motors. Pull at least six inches of wire into the
enclosure and complete the wiring connection according to the wiring diagram.
Figure 6.
This is a 3-wire sourcing device. Connect the plus DC or the AC voltage hot
side to the PWR terminal and the common is connected to the COM terminal. The
device is reverse voltage protected and will not operate if
connected backwards. It has a half-wave power supply so the supply common is
the same as the signal common. Several devices may be connected to one power
supply and the output signals all share the same common. Use caution when
grounding the secondary of a transformer or when wiring multiple devices to
ensure the ground point is the same on all devices and the controller.
The CO₂ analog output is available on the CO₂ terminal. This signal is switch
selectable for either 4-20 mA or voltage output (0-5 / 0-10 Vdc) see Figure 7
and connects to the controller analog input. Check the controller Analog Input
to determine the proper connection before applying power. Both current and
voltage signals are referenced to the COM terminal. The current output
operates in the active mode and does not require a loop power supply (the
signal current is generated by the transmitter and must not be connected to a
powered input or device damage will result).
The optional relay output connects to the RELAY terminals. The relay output is
completely isolated and has a Normally Open (NO) signal. This signal can be
used to directly control an alarm or ventilation fan. See specifications for
contact ratings. See Figure 8.
The optional override signal is a two-wire dry contact normally open switch
connected to the SWITCH terminals. See Figure 9.
The optional setpoint signal is a resistive signal that can vary from 0-10K
ohms (for example) to simulate a slidepot action. It is available on the
SETPNT terminal and is referenced to COM. Several resistive values are
available and the operation may be configured as normal or reverse acting via
the Setup Menu. See Figure 9
The optional two-wire temperature sensor output is available with various RTDs
and thermistors to suit all control applications and is available on the TEMP
terminals. See Figure 9.
OUTPUT SCALING
The CO₂ output signal is scaled such that 4-20 mA (or 0-5 / 0-10 Vdc) equals
0-2000 ppm by default. The signal span may be changed via the Setup Menu from
1000 to 10,000 ppm in 500 ppm increments.
START-UP MODE
Verify the device is properly wired and connections are tight. Ensure the mA /
VOLT switch is set for the correct signal type. Apply power and the LCD will
indicate the software version number, the output signal type and then the
sensor will begin a one minute warm-up countdown. When the warm-up time
expires the device will enter normal mode.
NORMAL MODE
The sensor will begin reading the CO₂ level (and temperature if it is
installed), output the correct analog signal and display the values on the
LCD. If the relay is installed, the measurements will be compared to the
setpoint and appropriate action taken. The keypad is monitored and if the
