Detcon 700 HRT Bridge - Manual (Page 16)

HRT Bridge
700 Sensor HRT Bridge IM Rev.0.2 Page 12 of 18
factory default setting and recommendation for span gas concentration is normally 50% of range. If a span gas
containing the recommended concentration is not available, other concentrations may be used as long as they
fall between 5% and 100% of range. However, any alternate span gas concentration value must be set in the
“Auto Span Level” field before proceeding with “Autospan cal”.
CAUTION: Verification that the calibration gas level setting matches the calibration span gas
concentration is required before executing “Autospan Cal”. These two numbers must be equal. Refer
to the appropriate sensor manual for more information.
1. If applicable install the Calibration Adapter or Splash Guard Adapter with integral Cal Port.
2. Verify that the Auto Span Level is equal to the calibration span gas concentration. If the Auto Span Level
is not equal to the Calibration span gas concentration, adjust the Auto Span Level.
3. Connect the Cal Gas to the sensor, but do not apply the gas.
4. Select “Autospan Cal” from the Sensor Calibration section of the screen.
NOTE: Upon entering calibration the 4-20mA signal drops to 2mA and is held at this level until the
program returns to normal operation.
5. Upon entering the procedure the procedure will prompt to begin Auto Span Calibration.
6. The procedure will prompt to apply span gas. Apply span gas from the attached cal gas cylinder and
respond to the prompt.
NOTE: The sensor reading will respond to the gas and will switch to displaying a flashing “XX”.
NOTE: Assuming acceptable sensor signal change, after 1 minute the reading will auto-adjust to the
programmed Auto Span level. During the next 30 seconds, the Auto Span sequence checks the sensor for
acceptable reading stability. If the sensor fails the stability check, the reading is re-adjusted back to the
Auto Span level and the cycle repeats until the stability check is passed. Up to three additional 30-second
stability check periods are allowed before the unit reports a “Stability Fault” twice and the sensor will
return to normal operation, aborting the Auto Span sequence. The sensor will continue to report a
“Stability Fault” and will not clear the fault until a successful Auto Span is completed.
NOTE: If the sensor passes the stability check, the sensor reports a series of messages:
“Span OK”
“Sensor Life XXX%”
“Remove Span Gas”
NOTE: When calibrating O2 deficiency sensors, there is no requirement to clear to <5% of range. The
sensor will return to normal operation immediately after span adjustment.
7. When the sensor passes calibration the procedure will prompt to remove the span gas. Unsuccessful
completion of the span calibration will create a Global Fault, and “Autospan Cal” will be aborted with a
change to the HART Sensor Status (refer to section 4.2.2 Sensor Status).
8. After successfully setting span cal the sensor and the HART Interface will return to Automatic Mode.
9. The Auto Span Calibration is complete
10. Remove the cal gas and calibration adapter if applicable.
NOTE 1: If the sensor fails the minimum signal change criteria, a “Range Fault” will be declared and a
“Fault Detected” message will be displayed alternately on the sensor with the current reading. The
HART Sensor Status will change to reflect a Range Fault.