VALTRONICS MODEL 2008SDH-2AP
CARBON DIOXIDE MONITOR
INSTRUCTION MANUAL
Copyright 2017 VTI-Valtronics Inc.
5
III. INSTALLATION
A. Circuit Board
Place the unit on a flat mounting surface in the area where the presence of carbon dioxide
is to be monitored or controlled. Mount the board on stand-offs using screws through
holes in the corners of the board.
B. Wiring
(See Figure 1)
The J1 connections by number are as follows:
1
Positive
12VDC Power Input
2
Ground
Common / Return for 12VDC
3
0-1V
0-1VDC Output
4
Ground
Common / Return for 4-20mA and 0-1VDC
5
4-20mA
4-20mA Output
C. Start-up Precaution
1.
Before applying power and placing the unit into operation, insure that the wiring
is correct.
2.
Do not install sensor or interface cable near transformers, fans or power line-
cords.
3.
Make sure that the 12VDC power supply (11 to 16VDC) has at least a 0.5 amp
capacity. The unit does not require a regulated supply.
4.
A dedicated power supply will also help avoid any ground-loop problems with
recorders or control circuits connected to the signal output of the unit.
5.
Separate wires are required for both the Common 4-20mA output and the
Common 0-1V output (if using both).
IV. OPERATION
(See Figure 3)
1.
Apply 12VDC power to the unit and allow 5 minutes for warm-up.
2.
Connect a multimeter to the 0-1V output signal, pins 3 and 4 of J1. With “outside” fresh
air, assumed to contain between 300 to 400 ppm CO2, the reading should be 0.000 volts.
3.
Apply CO2 gas through the gas cell – an amount equal to or lower than the “full-scale” of
the unit. Example: if you are checking a 2008SDH-2AP 100% unit flowing 100.00% gas
through the gas cell at a flow rate of about 50ml/min., it should produce a reading of
1.00V ± .050. 50.00% gas should produce a reading of 0.5V ± .025.
4.
If the readings are off, refer to Section V (SERVICING) for instructions on how to re-
calibrate the unit.
