Oldham TCOD-IR, Operating Instructions Manual

Page: 11 / 21

11
I
I
X
X
.
.
T
T
e
e
s
s
t
t
G
G
a
a
s
s
e
e
s
s
Only certified test gases must be used. For calibration, the test gas concentration must be
known to
±
2% relative to the bottle value.
Zero gas: 100% Vol. N
2
(nitrogen)
Standard Test Gas: CO
2
(carbon dioxide) above 2nd alarm level or in upper third of
measuring range.
WARNING:
Ambient air must not be used for zero-point adjustment.
The logarithmic response characteristic of the IR sensor element generates a large signal with
CO
2
. Concentrations in ambient air (> 400 ppm) would lead to a in accurate calibration.
X
X
.
.
M
M
a
a
i
i
n
n
t
t
e
e
n
n
a
a
n
n
c
c
e
e
a
a
n
n
d
d
C
C
a
a
l
l
i
i
b
b
r
r
a
a
t
t
i
i
o
o
n
n
i
i
n
n
t
t
e
e
r
r
v
v
a
a
l
l
s
s
.
.
Maintenance of the transmitter should be carried out at 12-months intervals by a specialist with
the recommended test gases and in accordance with the calibration and test procedures.
X
X
I
I
.
.
M
M
a
a
l
l
f
f
u
u
n
n
c
c
t
t
i
i
o
o
n
n
S
S
T
T
A
A
T
T
U
U
S
S
•
Should, during test span adjustment, fail if the potentiometer S had been turned clockwise
as far as possible and the position of the jumper J2 has been changed, the sensor may be
damaged due to dust or ageing and needs to be changed.
•
Should the output current be approx. 0 mA, the sensor element is probably faulty. In this
case, the sensor element should be replaced and the sensor re-calibrated.
X
X
I
I
I
I
.
.
A
A
c
c
c
c
e
e
s
s
s
s
o
o
r
r
i
i
e
e
s
s
a
a
n
n
d
d
S
S
p
p
a
a
r
r
e
e
P
P
a
a
r
r
t
t
s
s
Calibration Set
To guarantee the performance of the gas detection system, regular calibration should be carried
out.