Mipex MIPEX-04, Руководство пользователя, Страница: 34 / 41

Optosense LLC USER MANUAL
Design department MIPEX-04 ULTRA-LOW POWER INFRARED GAS SENSOR
ESAT.100000.00.02 UM Revision 02 December 12th, 2016 Page 34 of 41
THE SOLE PROPERTY OF OPTOSENSE LLC. ANY REPRODUCTION WITHOUT THE WRITTEN PERMISSION OF OPTOSENSE LLC IS PROHIBITED.
APPENDIX D. SENSOR CONFIGURATION
Appendix D.1. Zeroing and span calibration
Sensor zeroing and span calibration must be carried out during its initial installation as well
as annually during the period of preparation for the test. It is also recommended to perform zeroing
when sensor status
word “
31
” shows up (see Appendix F, Table 15 and Table 16). In any case
zeroing operation should be done before span calibration. For the list of CGMs recommended for
span calibration, see Table 13 and Table 14.
1. Covering gas-sampling holes of sensor increases response time (T90).
2. While span calibration is being carried out, avoid:

excessive pressure on sensor housing,

>98% humidity,

pressure of flowing gas less than 99 kPa and more than 103 kPa;

temperature change faster than by 0.6 °C/min,

dust ingress (if dust filter is not used),

data request rate more than 0.5 Hz.
Zeroing and span calibration should be carried out by qualified personnel outside of an
explosive area under normal conditions in the following sequence:
1. Communicate sensor via UART interface (example based on MIPEX-04 interface board
ESAT.200100.00 is shown on Fig. 12; gas adapter ESAT.200105.00 is available as an
option).
2. Auto-zeroing procedure of sensor concentration readings is started automatically during
sensor self-diagnostics after power is switched on. Sensor self-diagnostics runs
constantly while power is on. Use the following commands to control the algorithm:
<AZERO ON>, <AZERO OFF> and <AZERO?>. However, if zero shifts anyway, it is
recommended to perform zeroing manually:
2.1. within 5 minutes after power was supplied start feeding CGM #1 (high purity
nitrogen) into sensor atmosphere;
2.2. one minute after CGM #1 was supplied, send command <ZERO2>; thus sensor
readings on the concentration will be set to zero;
2.3. stop feeding CGM #1 into sensor atmosphere.
3. Start feeding CGM #2 into sensor atmosphere.
4. One minute after CGM #2 was supplied, send <CALB AAAA> command, where AAAA is
a value of CGM concentration (e.g. value 0198 corresponds to 1.98% vol.). Thereafter
scaled concentration value C
1
becomes equal to the sent value AAAA. Scale coefficient
is stored in sensor microcontroller memory until the next span calibration. Before
sending command <CALB AAAA>, ensure the following conditions: