GF Signet 2610 MODBUS Process Optical Dissolved Oxygen Sensor - Manual (Page 4)

4 2610 DO Sensor MODBUS Manual
Calibrate the sensor using the following procedure:
1. Optional: Read the Sensor Data Cache Timeout register 49463 and store the value.
2. Write the Sensor Data Cache Timeout register 49463 to a value less than your intended sample rate
and greater than 1000 milliseconds. This will ensure that you get new sensor readings during the
stabilization process.
3. Optional: Read the temperature units register 40049 and saturation units register 40041 and store their
values.
4. Write the temperature units register 40049 to its default value (1) and write the saturation units register
40041 to its default value (117).
5. Write the Calibration Mode On command (0xE000) to the sensor command register 49305.
6. Update the live salinity and barometric pressure registers if necessary.
7. Prompt the user to place the probe in a 100% saturation environment.
8. Read the oxygen concentration and temperature parameters. When these values have reached
equilibrium, record them in their respective 100% saturation calibration registers. Write the current live
salinity and barometric pressure readings to their respective calibration registers.
9. Prompt the user to place the sensor in a 0% saturation environment. When these registers have
reached equilibrium, record them in their respective 0% saturation calibration registers. If a zero
calibration is not to be performed, these registers can be set to zero or left at their previous values.
Note: If you have a version of RDO PRO fi rmware that is earlier than 1.15 and you are not doing the
zero calibration, you must set the 0% calibration registers to zero.
10. Write the Calibration Update command (0xE001) to the sensor command register. The sensor will
calculate a new slope and offset, write the current time to the last user calibration time register, and
set the next user calibration time register to zero (disabled). If the concentrations at 100% and 0%
saturation are equal, the probe will return an exception response with code 0x97 (invalid calibration)
and not attempt to compute a new slope and offset due to possible division by zero. If the slope does
not calculate between 0.85 and 1.20 inclusive, or the offset does not calculate between -0.2 and +0.2
inclusive, the probe will return an exception response with code 0x97 (invalid calibration).The slope and
offset will be available for read but will not be committed to fl ash.
11. Optional: Read the last user calibration time register, add the next calibration interval, and write the
result to the next user calibration time register.
12. Write the Calibration Mode Off command (0xE002) to the sensor command register to place the sensor
in normal operation. If the calibration mode is turned off without a calibration update command, or the
calibration command returned an exception, the previous calibration shall be restored.
13. Optional: If you saved the temperature and saturation parameter units at the start of the process, write
the original values back.
14. Optional: If you saved the Sensor Data Cache Timeout register 49463 at the start of the process, write
the original value back.
Entering Calibration Registers
IMPORTANT
Calibration is not required. The sensor cap is factory calibrated to 2% accuracy.
This is valid for the life of the sensor cap, one year from fi rst reading.