In order to prevent additional calibration errors caused by temperature variations, turn on the equipment and preheat it for at least half an hour. This will allow the internal analogue circuitry to fully stabilise thermally.
Create a reference process calibrator that has an accuracy class of at least ±0.01%. As a traceability baseline for accuracy comparison, its accuracy class needs to be at least two classes higher than the signal generator undergoing calibration.
Make sure all test cables are securely fastened. Make that the apparatus is consistently grounded. Electromagnetic interference should be eliminated by maintaining a constant temperature of 23±5°C and a humidity level of no more than 80%.
Step 1: Basic Self-Test and Zero-Point Calibration: Choose the "Self-Test" option from the signal generator system settings menu. Verify that there are no hardware issues and that the device is operating as it should.
Leave the signal generator output port empty and disconnect all external loads. Choose "Zero-Point Calibration" from the system calibration menu.
Await the equipment to automatically reset the zero-point deviation compensation to zero and obtain the real zero-point output value under the current unloaded state. Verify that the output deviation at zero is less than 0.01% of the range.
Step 2: Basic Self-Test and Zero-Point Calibration: Choose the "Self-Test" function from the signal generator system settings menu. Verify that there are no hardware issues and that the equipment is stable. Step 2: Calibration of Full-Range Accuracy
Using a reference calibrator, measure the actual output value point-by-point after setting the signal generator output sequentially to 10%, 25%, 50%, 75%, and 100% of the range.
To ensure that the full-range output deviation is below the nominal accuracy of the equipment, eliminate nonlinear variations across multiple ranges by adjusting the gain correction coefficient of the appropriate channel for each range.
Particular Thermal Signal Calibration: To rectify temperature analogue signal errors and satisfy the hot runner temperature control channel's calibration criteria, calibrate the thermocouple millivolt output and RTD resistance output point-by-point.
Frequency calibration involves setting the output frequency of the signal generator to 10MHz, using a high-precision frequency counter to measure the actual output frequency, adjusting the frequency correction coefficient until the deviation is zero, and concentrating on calibrating frequently used frequency bands throughout the whole frequency range.
Waveform Distortion Calibration: Produce a 1 kHz sine wave, use an oscilloscope in THD mode to evaluate the waveform distortion, modify the waveform optimisation parameters, and make sure the THD does not beyond the technical limitations of the apparatus.
Step 3: Archiving and Post-Calibration Verification
After calibration, run the system continuously for an hour, gathering output data from important verification points every ten minutes to ensure that there is no continuous offset and the drift amount during the hour is ≤0.03% of the range.
To ensure that there are no signal jumps or communication disruptions and that the difference between the temperature control system display value and the signal generator output value is ≤±1℃, connect to the hot runner temperature control system and run a full-channel linkage test.
The device is prepared for official use once all verification items satisfy the requirements, the calibration parameters are saved to the non-volatile memory of the device, and a calibration record is created for archiving.
