User manual HONEYWELL C7110A

[. . . ] Registered Trademark Copyright © 2009 Honeywell Inc. · All rights reserved EN0B-0295GE51 R0409 C7110A ROOM AIR QUALITY SENSOR FUNCTION The electrical conductivity of a heated tin-dioxide semiconductor sensor varies in proportion to the number of molecules of the reducing agents. This leads to a voltage at the measuring element which is amplified to an output voltage of 0 to 10 Vdc. [. . . ] Twisted pair wire is recommended for wire runs longer than 100 ft (30. 5 m). Keep wiring at least one ft (305 mm) away from large inductive loads such as motors, line starters, lighting ballast, and large power distribution panels. Run wall module wiring separately from 50 Vac or greater power wiring. 60 104 Positioning To avoid falsifying the measuring results, the device should be installed at sites at which typical air quality prevails. Direct exposure to sunlight and drafts should be avoided. If the device is mounted on a standard flush box, the end of the installation tube in the flush box must be sealed so to avoid any draft in the tube falsifying the measuring result. Fig. 3 Dimensions and mounting holes (mm) EN0B-0295GE51 R0409 C7110A ROOM AIR QUALITY SENSOR IMPORTANT Screw-type terminal blocks are designed to accept no more than one 16 AWG (1. 5 mm2) conductor. Connect the wires to the terminal block as follows: a) Strip 3/16 in. (5 mm) of insulation from the conductor. b) Insert the wire in the required terminal location (see Fig. 5) and tighten the screw to complete the termination. 4 and make sure that the tab on the underside engages. Adjust the trimming potentiometer offset (see section "Adjusting the Trimming Potentiometer Offset"). When the air quality deteriorates, the voltage of the output signal will rise. OUT GND 24V/AC +(15-30) V/DC Fig. 5 Wiring Connection and Trimming Potentiometer · · Turning the potentiometer counterclockwise decreases the output signal. Turning the potentiometer clockwise increases the output signal. 1 The sensor cannot distinguish pleasant from unpleasant smells. The final adjustment whether air quality is satisfactory or not must be made by the persons living or working in the room. Moreover, various air compositions are occurring in different rooms. Thus, the default (factory) setting of the setpoint is provisional, only. [. . . ] The offset of the output signal is increased or lowered by means of this potentiometer. 3 EN0B-0295GE51 R0409 C7110A ROOM AIR QUALITY SENSOR EXAMPLE OF DYNAMIC BEHAVIOR Fig. 6 shows the dynamic characteristics of the air quality sensor, monitored during test measurements in a sample room. This voltage diagram as a function of different occupancy conditions is only an example and must be proven for other ambient conditions. 10000 9000 8000 voltage (mV) 7000 10000 6000 5000 4000 3000 2000 1000 0 ALL THREE PERSONS HAVE VACATED ROOM. [. . . ]