Bacharach 3015-4286 manual Working with the Calibration Function, Calibration Procedure, Overview

Working with the Calibration Function

Overview

If greater than standard accuracy is desired, the factory’s default calibration factor of 1.000 may be adjusted by performing the calibration procedure as described below, and then selecting the monitor’s CAL function to enter the new calibration factor.

IMPORTANT! Changing the calibration factor will VOID the factory calibration. Typically, the monitor will remain within the factory-calibrated accuracy indefinitely and no calibration is required. Complex software algorithms adjust for temperature drift, IR source aging, and pressure changes in order to keep the unit within factory accuracy specifications.

Calibration Procedure

The calibration factor is determined by sampling a known dilution of ammonia gas. The sample must be prepared to less than half the desired accuracy and the concentration must be corrected for ambient temperature and pressure at the time of measurement.

Calibration is best performed at or near full scale, it can however, be done at any concentration and ideally in the range where maximum accuracy is desired down to, but not below, 100 ppm.

A cylinder of a certified calibration gas must be used to ensure sampling occurs at ambient conditions. A minimum sample size of 5 liters is required.

The AGMSZ should be operating for at least one hour prior to performing a calibration.

Prepare the AGMSZ for sampling by using the CAL function to set the calibration factor to 1.000. Also, use the LOG INT function to set the log interval to 1 minute.

With the AGMSZ operating normally, connect the gas-sample bag directly to the gas-inlet port and allow the monitor to sample the entire bag. When sampling is complete, view the logged ppm values using the PPM LOG function. If the bag was large enough for multiple samples, average the most stable ones. The new calibration factor is computed by dividing the known gas concentration value by the measured value. Typically this number will be between 0.95 and 1.05. Use the CAL function as described below to enter the new calculated calibration factor

Adjusting Calibration Factor

From the Data Display screen, use the Keypad buttons to place the arrow (>) on the display next to the CAL function. Then press ENTER to display the Calibration screen.

R717 CALFACTOR

1.000

With the Calibration screen displayed, use the Keypad buttons to enter the new calibration factor. Press ENTER to save this value.

22 Instruction 3015-4286