I. Preparation and Status Confirmation Before Calibration
Start the hot runner signal generator and preheat for at least 30 minutes to allow the internal crystal oscillator and analog circuitry to reach thermal stability, eliminating initial deviations caused by temperature drift.
Prepare a CR5018 process signal calibrator with an accuracy class ≥ ±0.01% as the calibration reference device. This device supports high-precision measurement of all types of thermal signals, including voltage, current, RTD, and thermocouple signals, fully meeting the accuracy calibration requirements of the hot runner signal generator.
Perform a system self-test, disable all AM, FM, and other modulation functions, and uniformly select a standard DC/sine wave as the output waveform to avoid additional signal interference during the calibration process.
II. Frequency Reference Accuracy Calibration
Set the signal generator output frequency to a typical value of 10MHz and use a high-precision frequency counter to measure the actual output frequency.
If the measured value deviation exceeds ±1ppm, enter the "Frequency Calibration" menu and adjust the frequency correction factor until the deviation is zero.
The calibration covers the entire frequency range, with a focus on calibrating the 10kHz, 1MHz, and 10MHz frequency bands commonly used in hot runner verification to ensure clock reference accuracy meets standards.
III. Voltage/Current Output Accuracy Calibration
Voltage Calibration: Set the signal generator to output 0~10V DC voltage. Using the high-precision measurement value of the process calibrator as a reference, adjust the voltage gain correction coefficient point by point until the full-range voltage output deviation is ≤±0.01%.
Current Calibration: Set the signal generator to output 0~24mA DC current. Using the measurement value of the process calibrator as a reference, adjust the current gain correction coefficient point by point until the full-range current output deviation is ≤±0.1μA.
IV. Thermal Signal Specific Accuracy Calibration
Thermocouple Signal Calibration: Set the signal generator to output millivolt analog signals of commonly used thermocouples such as K-type and J-type. Using the millivolt measurement value of the process calibrator as a reference, adjust the thermocouple output correction coefficient to ensure that the temperature simulation output accuracy matches the verification requirements of the hot runner temperature control channel.
RTD signal calibration: Set the signal generator to output simulated resistance signals from common RTDs such as Pt100 and Cu50. Using the resistance measurement value from the process calibrator as a benchmark, adjust the RTD output correction coefficient to ensure the simulated resistance output deviation is ≤ ±0.05%FS.
V. Full-range accuracy verification and parameter solidification
After all calibrations are completed, randomly select 10 calibration points across the full range and measure the output value one by one using the process calibrator to confirm that the accuracy deviation at all points is within the allowable range.
Run the equipment continuously for 30 minutes, collecting output accuracy data every 5 minutes to confirm no instability due to time drift.
Save all calibrated frequency correction coefficients, gain correction values, and thermal signal correction coefficients to the equipment's non-volatile memory. These parameters will not be lost after a power outage and restart.
Record all parameter values from this calibration to generate a calibration file, providing a comparison benchmark for subsequent periodic recalibrations.
This accuracy calibration process is fully adaptable to hot runner industrial field operation and maintenance scenarios. The operation steps are clear and practical, enabling rapid, full-dimensional, high-precision calibration of the hot runner signal generator.
