In order to prevent additional calibration problems caused by temperature variations, turn on the device and warm it for at least half an hour. This will allow the internal analogue circuitry to fully thermally stabilise.
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 sure the gadget 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 "Self-Test" from the system settings menu of the signal generator. Verify that there are no hardware issues and that the gadget is operating normally.
Leave the signal generator output port empty and disconnect all external loads. Choose "Zero-Point Calibration" from the system calibration menu.
Await the device to automatically reset the zero-point deviation compensation to zero and obtain the real zero-point output value in the current unloaded condition. 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" option from the system settings menu. Verify that there are no hardware issues and that the device is reliable. 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.
Step 3: Verification After Calibration
Run continuously for an hour after calibration, gathering output data from important calibration points every ten minutes to ensure that there is no continuous offset and the drift during an hour is less than 0.03% of the range.
Engage the hot runner temperature control system and conduct a full-channel linkage test to verify that there are no signal jumps or communication disruptions and that the difference between the output value of the signal generator and the temperature control system's displayed value is ≤ ±1℃.
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.
In order to ensure that the hot runner signal generator's calibration accuracy satisfies the needs of the production line, regular industrial control system maintenance experts can independently conduct this simple and straightforward calibration process without the need for additional sophisticated gear.
