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DT5-1112-2B11 – UserManual
Page 03
Specifications subject to change without notice. | USA 150929 | Page 3 of 19
Electrochemical Carbon Monoxide Transmitter
1 General Overview
The PolyGard CO BACnet gas transmitter DT5-1112-2B11 with digital processing of the measuring values and
temperature compensation is used for the continuous monitoring of the ambient air to detect the presence of
carbon monoxide gas. Applications include underground / enclosed parking garages, tunnels, engine test
stations, shelters, loading areas etc.
The DT5-series transmitter is equipped with a serial interface including BACnet protocol and with an analog
output where the signal can be selected as current signal (0)4-20 mA or as voltage signal (0)2-10 V. In the 4-20
mA mode the transmitter also works in the 2-wire technique. Addressing and calibration is done manually via
push-buttons / potentiometers and address switches.
The intended installations are all areas being directly connected to the public low voltage supply, e.g.
residential, commercial and industrial ranges as well as small enterprises (according to EN50 082).
The PolyGard® CO BACnet transmitter must NOT be used in potentially explosive atmospheres.
2 Functional Description
2.1 Control Mode
The transmitter can be connected via RS 485 Interface / BACnet protocol to a vide variety of monitoring and
control devices such as, Direct Digital Controllers, Single/Multi-point controllers, Building Management
Systems, Personal Computers etc. In this mode there is an analog input for the connection of an additional 420 mA transmitter. The two measuring values are transmitted via the RS-485 interface / BACnet protocol.
The cable topology for the RS-485 bus can be taken from the “Guidelines for wiring and commissioning of the
DGC-05 hardware”.
2.2 Sensor
The sensor portion of the transmitter is a sealed electro-chemical cell with two electrodes, sensing and
reference. The ambient air to be monitored diffuses through a membrane filter into the liquid electrolyte of the
sensor. The chemical process of the measurement is one of oxidation where one molecule of the target gas is
exchanged for one molecule of oxygen. The reaction drives the oxygen molecule to the counter electrode,
generating a DC microampere signal between the sensing and reference electrodes. This signal is linear to the
volume concentration of the sensed gas. The signal is evaluated by the connected amplifier and transformed
into a linear output signal.
Electrochemical processes always lead by-and-by to a loss of sensitivity. Therefore calibration of zero-point
and gain via BACnet or with the potentiometer “Gain” is necessary at regular intervals.
Caution:
There is a small quantity of corrosive liquid in the sensor element. If in case of damage persons or objects
touch the liquid, you have to clean the affected areas as fast and carefully as possible with tap water. Out of
use sensors must be disposed in the same way as batteries.
Polygard® is a registered trademark of MSR | GAADT031110BAC_0412
12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: (858) 578.7887 & (888) GO.INTEC | relevantsolutions.com/inteccontrols
Printed in USA 140916