Reference Instrument Accuracy Verification: Directly measure the signal generator's output value at zero point using a reference process calibrator with an accuracy class > ±0.01%.
The DC current zero point deviation must be ≤ ±0.001mA, and the DC voltage zero point deviation must be ≤ ±1μV. If these ranges are exceeded, the zero point adjustment is not justified.
Thermal Signal Specific Verification: Pt100 RTD zero point resistance deviation < ±0.01Ω and thermocouple millivolt zero point deviation ≤ ±0.5μV fully satisfy the zero point accuracy criteria of hot runner temperature control calibration.
Verification of Zero Point Stability: After adjusting the zero point, let the apparatus stand for half an hour before taking another measurement of the zero point output value. Verify that there is no zero point bounce and that the zero point offset is ≤ 0.02% of the range.
For one hour, run the machine nonstop, gathering zero point output data every fifteen minutes. Without any instability brought on by a continuous change over time, the zero point drift must not surpass 0.03% of the range in less than an hour.
In order to check that there is no zero-point drift due to internal solder joint problems, a slight vibration of the equipment casing should create zero-point output fluctuations lasting ≤2 seconds without any aberrant jumps.
Verification of Environmental Adaptability: During 30 minutes of operation at 60°C, the zero-point drift should not surpass 120% of the zero-point deviation at room temperature, and there should be no abrupt rise in temperature drift.
The zero-point output should be stable and free of zero-point inaccuracy problems after 30 minutes of operation at -10°C.
Verification of Hot Runner System Interconnection: Upon connecting to the hot runner temperature control system, every channel should produce the thermal simulation signal that corresponds to 0°C. This ensures that every temperature control channel's difference between the displayed temperature and the theoretical zero-point temperature is ≤±0.5°C.
All temperature control channels' zero-point temperature displays should exhibit no jumps or drifts after two hours of continuous operation, perfectly matching the hot runner production line's actual usage needs.
The equipment can be formally put into regular operation in the hot runner production line once all verification items have met the requirements and the zero-point adjustment is considered fully approved.
