35. PERIOD BETWEEN GAS AUTOCALS
Set the number of hours between autocal Gas 1. A typical time would be 24 or 168 hours. (Daily of weekly).
Range:
1 to 1999 hours. The default setting is 1 hour.
36. DURATION OF AUTOCAL GAS
Set the number of seconds that the autocal gas solenoid will be open. At the end of this period, if the oxygen level
measured is not within the limits set for Cal Gas, a ‘GAS CAL ERR’ will initiate. To determine the minimum time
required for a particular configuration of Analyzer to settle, manually admit cal gas while observing the oxygen reading
in ‘RUN’ mode by pressing the ‘CAL 1’ button. Typical minimum times vary from 5 to 15 seconds.
Range:
0 to 90 seconds. The default setting is 10 seconds.
37. FREEZE TIME GAS
After the Cal Gas period, the transmitter output will remain fixed, (frozen) for an adjustable period to allow the sensor
reading to return to the correct process level and avoid output ‘bumps’. The freeze period time required will depend on
the sensor response time.
Range:
10 to 100 seconds in ten second steps. The default setting is 30 seconds. To determine the required freeze time,
manually perform a calibration check with Gas 1 while the plant is in operation and note the time required for the
reading to return to the correct process level within approximately 0.5 % oxygen.
38. RESET LEVEL
The RESET level is the trip level which triggers the sampling mode capture of the oxygen level.
By setting the reset level below
20.9% the Analyzer will capture a minimum oxygen level.
By setting the reset level above
20.9% the Analyzer will capture a maxiimum oxygen level.
In order to detect a new ‘SAMPLE’ oxygen or carbon dioxide level, the oxygen reset threshold must be set below (or
above for peak capture) the normal idle oxygen level, but well above (or below for peak capture) the level expected in
the sample period.
This level will not be used if ‘Continuous’ is selected in set-up 26.
Range:
0.1 –100.0% oxygen. The default setting is 15.0 % oxygen.
39. HIGH OXYGEN ALARM
Set the operating point for the high oxygen alarm relay.
The high oxygen alarm has a dual range selected by a link on screw terminals 14 & 15 ( FUEL 1/2 ). If the link is
NOT connecting the two terminals, the range will be 0.1 to 30.0 % oxygen. If the terminals have a short circuit link
between them, the range will be 10 to 3000 ppm oxygen.
Range:
0.1 – 30.0% oxygen. The default setting is 10.0 % oxygen.
10 – 3000 ppm oxygen. (With screw terminals 14 & 15 linked)
40. HIGH OXYGEN DELAY ( only available if ‘Continuous’ is selected in Set-up 26 )
Typically set at 30 seconds. This delay is to avoid nuisance alarms when the burner is undergoing transitions in firing
rate which can cause it to deviate from the oxygen set point, but recover quickly.
Range:
0–200 seconds. The default setting is 60 seconds.
Teledyne Analytical Instruments 9070 Oxygen Analyzer Page 37
