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TVOC MANUAL
6
Operation
6.1 Start Up
After electrical power is connected, TVOC runs through a 'Start up' routine, which lasts for approximately 1
minute. During this 'Start up' routine TVOC demonstrates the following characteristics:
* The LCD screen displays the software version number
* The GREEN LED flashes
* The 4 – 20 mA output is set to 4 mA (0.0 ppm)
NOTE: If the 0-10ppm range is selected the TVOC will require calibration using 10ppm Isobutylene before
user (See the calibration section of this manual)
During this 'Start-up' time the user can adjust the lamp OFF time as referred to on page 10. This time can be
adjusted from 0 to 5 minutes in 1 second increments.
6.2 Cycle times
To extend PID lamp life and the time between servicing, TVOC includes a
variable duty cycle, (see section 4.2) whereby the lamp is switched ON
and OFF. The length of time between servicing and calibration is
increased where longer OFF times are selected. However the length of
time between servicing also depend on ambient air quality, the higher
VOC concentration detected by the instrument then the shorter the time
between servicing.
6.2.1 Adjusting the lamp OFF time
There are two stages to adjusting the lamp OFF time. The first stage adjusts the seconds (0-59) and the
second stage adjusts the minutes (0-5). To adjust the lamp OFF time the magnetic switch must be activated
during the 'Start-up' time.
NOTE: Please read this entire procedure before attempting to adjust the lamp OFF time.
1 – During the 1 minute 'Start up' routine place the calibration magnet over the top
right hand corner of the Ion Science logo.
2 - This indicates the lamp OFF time in seconds.
3 – Placing the calibration magnet back over the logo will cause the number to role between 0 and 59
seconds. Remove the magnet when the desired time is displayed.
4 – After 5 seconds the display will show another two numbers and flash.
5 – This indicates the lamp OFF time in minutes.
6 – Again place the calibration magnet over the logo to rotate the numbers between 0
and 5 minutes. Remove the magnet when the desired time is displayed.
7 - After 5 seconds the entire output frequency is displayed.
8 - After a further 5 seconds the set frequency will be set in the
TVOC memory.
9 - TVOC then continues through the standard start-up routine.
If you are unhappy with the update frequency you have set you can adjust the time by placing the
calibration magnet over the logo during the 5 seconds after the total time has been shown (point 8 above).
NOTE: The total duty cycle time includes the 5 seconds lamp ON time. Therefore if you wish your total duty
time to be approximately 2 minutes set the lamp OFF time to 1 minute 55 seconds.
At the end of the 'Start up' routine TVOC will enter the selected monitoring routine.
Two numbers on the LCD screen will flash.
Page 15 of 28
Ion Science Ltd
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