AMC 1ACO, Инструкция по эксплуатации, Страница: 19 / 22

Gas Monitor 1ACO One-Channel Monitor
17
calibrates the sensor and allows alarm thresholds to be set between no gas and full range gas
levels.
Connect the negative lead of the multimeter to TP7 AGND
1) Obtain access to AMC-S2e (CO). Remove cover of 1ACO so gas can be applied
directly to the sensor and signal pot can be adjusted.
2) Attach multi-meter to measure the output signal; positive lead to TP4 and negative
lead to TP7 AGND
3) Apply the span gas sample (100ppm CO) with the calibration adapter cup firmly and
completely over the sensor for 2 minutes with flow rate 0.5 liters per minute. At 2 min
adjust the span trimpot R1 (refer to Figure 9) on the AMC-S2e(CO) for output signal
reading 3.3VDC +/- 2% (66mV)
4) In the presence of clean air (0 PPM CO), measure the output signal at TP4. Record
this value as V
LOW.
Use the following formula to determine what the output voltage of
the AMC-S2e(CO) will be for the gas concentration at which the alarm is to be
triggered.
V
ALARM
= ((C
ALARM
/ C
full scale
)*(1.32V - V
LOW
)) + V
LOW
Where
o
V
ALARM
is the voltage the alarm trip point will be set to.
o
C
ALARM
is the gas concentration at which the alarm is to be triggered.
o
C
full scale
is 100 PPM for the AMC-S2e-CO.
o
1.32V is level the AMC-S2e has been factory calibrated to for 100 PPM CO.
o
V
LOW
is the voltage measured in the previous step, representing the zero gas
output level
Adjust to appropriate alarm trimpot for the desired threshold.
•
For increasing thresholds, the ALARM threshold must be higher than the WARNING
threshold.
EXAMPLE 1: To set an ALARM threshold of 50 PPM with the AMC-S2e;
•
Install AMC-S2e, wait the stabilization period and measure the output signal at
TP4 and record as V
LOW
(use 0.380V for this example).
•
C
alarm
: 50 PPM
•
C
full scale
: 100 PPM (AMC-S2e is calibrated to this value at the factory)
•
V
alarm
= (( 50 PPM / 100 PPM) * (1.320V – 0.380V)) + 0.380V
= 0.850V
RV6 would be adjusted so that 0.850V is measured at TP6.
EXAMPLE 2: To set a WARNING threshold of 25 PPM with the AMC-S2e;
•
Install AMC-S2e, wait the stabilization period and measure the output signal at
TP4 and record as V
LOW
(use 0.380V for this example).
•
C
alarm
: 25 PPM
•
C
full scale
: 100 PPM (AMC-S2e is calibrated to this value at the factory)