Tech Tips - Proper Calibration Using Hand Samples

Lab samples are not always accurate. To help insure accurate calibration, please consider these guidelines before adjusting your transmitter.

Basic Calibration Rules

  1. Make an Output Adjustment when a series of lab results shows a consistent error in the same direction.
  2. After the First Zero Adjustment, output adjustments should be one half the error shown between the lab and the transmitter. Remember, the lab 
  3. sample also has an error, so you should not over correct.

Error Evaluation Rules

When does an error warrant an Output Adjustment TECO recommends two different tolerance ranges.

  1. 1st Tolerance range from no error to the maximum desired error. Recommended range of +/- 5% of the consistency output.
  2. 2nd Tolerance range from the maximum desired error to the maximum excepted error. Recommended range of +/- 10% of the consistency output.

Tolerance range of 5% and 10% are general guidelines that can be changed based on the application.

 Output Adjustment Guidelines
Error Recorded Output Adjustment Recommended
If the transmitter reads within the 1st Tolerance range (+/- 5 % error) Do not adjust the transmitter.
If the transmitter reads outside the 1st Tolerance range but within the 2nd Tolerance range (+/-5% to +/-10% error) Wait for your next scheduled sample test before making adjustments to the transmitter.
If the transmitter reads outside the 2nd Tolerance range +/-10% tolerance of the average sample. Verify error with an addition sample and make an output adjustment on the transmitter to correct the error.