I. Preparation Before Calibration
Power on the hot runner signal generator and allow it to warm up for at least 30 minutes to allow the internal crystal oscillator and analog circuitry to reach thermal stability.
Enter the device's "System Settings" menu and perform a system self-test to confirm that all channels have no hardware errors. Disable all AM/FM/PM modulation functions.
Prepare a process signal calibrator with an accuracy class ≥ ±0.01%, a high-precision frequency counter, and a multi-channel oscilloscope with a bandwidth ≥ 100MHz as reference equipment. Warm up the reference equipment.
II. Frequency Reference Calibration
Set the signal generator output to a typical 10MHz frequency and measure the actual output value using the frequency counter.
If the deviation exceeds ±1ppm, enter the "Frequency Calibration" menu and adjust the frequency correction factor until the deviation is zero.
Complete full-range calibration covering the commonly used 10kHz, 1MHz, 10MHz, and 100MHz frequency bands for hot runners.
III. Output Amplitude Calibration
Set the commonly used amplitude levels for hot runners at 10mVpp, 100mVpp, 1Vpp, 10Vpp, and 20Vpp point by point.
Measure the actual output value using a reference device. If the deviation exceeds ±1%, adjust the corresponding channel gain correction value.
For higher amplitude levels, enable the oscilloscope's high impedance input mode (≥1MΩ) to avoid additional deviations introduced by load effects.
IV. Thermal Signal-Specific Calibration
Thermocouple Calibration: Set the millivolt analog signals of commonly used K-type and J-type thermocouples. Using the measurement value from the process calibrator as a reference, adjust the thermocouple output correction coefficient.
Resistor Calibration: Set the resistance analog signals of commonly used Pt100 and Cu50 resistors. Using the measurement value from the process calibrator as a reference, adjust the resistor output correction coefficient to ensure a deviation ≤ ±0.05%FS.
V. Multi-Channel Synchronous Calibration
Using the rising edge of the main channel waveform as a reference, use a multi-channel oscilloscope to acquire all slave channel output signals and read the phase time difference of each channel. Fine-tune the delay correction coefficients channel by channel until the synchronization deviation between all channels and the main channel is ≤0.01s.
When the trigger line length exceeds 200 meters, enable the cable resistance compensation function to offset the synchronization delay caused by long-distance transmission.
VI. Verification and Parameter Consolidation
Randomly select 10 calibration points across the entire range for recalibration, confirming that the accuracy deviation of all points is within the allowable range.
Run continuously for 30 minutes, collecting data every 5 minutes to confirm that there is no instability due to drift over time.
Save all calibration correction coefficients to the device's non-volatile memory, generating a calibration file to complete the recalibration.
