SGX Sensortech VQ10 Manual

To be read in conjunction with "Introduction to Pellistor Gas
Sensors" and Pellistor Application Notes 1, 2, 3, 4, 6 and 7.
INTRODUCTION
The VQ10 consists of two matched elements which are used for
the detection of combustible gases, particularly methane in air
mixtures in concentrations from 0.1% upwards. There is no
interference from water vapour or carbon dioxide. Using the
recommended bridge circuit (see below) and the mounting
arrangement shown on page 2, the minimum sensitivity is
15 mV/% methane.
The low power consumption of the VQ10 makes it suitable for
use where the power consumption must be minimised, e.g.
battery operated systems.
GENERAL DATA
Electrical
The information given below relates to the VQ10 operating in
the recommended circuit shown.
Operation (see note 1) . . . . . . . . . continuous
Bridge supply . . . . . . . . . . . 2.0 + 0.1 V
Bridge power consumption (at 2.0 V)
Minimum sensitivity (see note 2)
Linearity . . . . . . . . .
1
Response time to register 1
concentration (see notes 2 and 3) . . . . 2
Maximum methane concentration
(see note 4) . . . . . . . . . . . 5
Mechanical
Mounting . . . . . . . . . . . . . . see page 2
Outline . . . . . . . . . . . . . . . see page 2
Shock test . . . . . . . 250 g, 5 blows in each plane
Vibration test . . . . 20 g, 24 cycles from 100 to 3200 Hz
BRIDGE CIRCUIT
2309C
1 kO
2 V
ZERO SET
SGX Sensortech(IS) Ltd Registered in England No.08067077
. . . 0.48 W max
. . . 15 mV/% methane
linear up to 3% methane
1
/ % in a 2 / %
4 2
seconds
COMPENSATOR
(BLACK SLEEVE)
27O
27O
DETECTOR
(RED SLEEVE)
OUTPUT
Combustible Gas Detector Elements
MARKING
Each element is identified by a unique serial number written on
the can of both the detector and compensator. The serial
number is written in red on the detector and black on the
compensator. In addition, the detector carries a red circular
label on the base identifying the device type.
NOTES
1. Operation may be under either direct flow or diffusion
conditions in appropriate mountings (see page 2).
2. With open-circuit conditions at the bridge output.
3. The response time is a function of the type of mounting
used.
4. If the VQ10 is exposed to greater than 5% methane
concentration, the calibration of the instrument should be
checked.
5. The elements are supplied as a matched pair with a
trimming resistor R of the correct value which is between
68 and 220 O. The trimming resistor is to be connected
across the compensator element as shown below.
6. The elements must be protected from certain organic and
silicone vapours by suitable filtering, and caution should be
exercised when operating in close proximity to hot, oily
machinery.
%
SEE
R
NOTE 5
VQ10
A1A-VQ10 Version 6, December 2008