I. Preparation Before Calibration
1. Environmental Requirements
Choose an indoor environment free from strong electromagnetic interference, with stable temperature (15℃～35℃) and moderate humidity for calibration to prevent external factors from affecting the results.
2. Tool Preparation
Standard speed source (e.g., a standard roller driven by an adjustable speed motor)
Digital multimeter, oscilloscope
DC regulated power supply (output DC12V～24V)
Ammeter (range 0～20mA)
3. Safety Confirmation
Ensure the sensor body is undamaged, properly sealed, and the wiring terminals are free from oxidation to prevent safety hazards during calibration.
II. Calibration Steps
1. Power Supply Connection
Connect the sensor's E (+) and O (-) terminals to a DC regulated power supply, setting the output voltage to DC12V. Confirm the operating current is ≤10mA (GS4(A) model as an example).
2. Setting the Rated Speed Gear
According to the actual usage scenario, open the sensor housing and set the speed gear switch to the corresponding value (e.g., 1.5m/s, 2.5m/s, or 3.5m/s).
3. Mechanical Connection and Drive
Close the sensor roller tightly to the standard speed roller, ensuring synchronous rotation without slippage. Start the standard speed source and set four test points: 50%Ve, 70%Ve, 100%Ve, and 110%Ve (Ve is the set value).
4. Signal Output Detection
Level Signal Calibration: When the speed reaches ≤50%Ve or ≥110%Ve, the sensor should output a low level (≤0.5V); between 70% and 110%Ve, it should output a high level (≥11V). Analog Signal Calibration: For models with an output of 4-20mA (e.g., GSH3.6(D)), the output should be 12mA ± 0.5mA at 100% Ve. Adjust the internal potentiometer W2 to ensure signal accuracy.
5. Response Time Verification: Simulate low speed (50%～70% Ve) for 10 seconds. Confirm that the sensor accurately flips the level signal at the 10th second, triggering the protection mechanism.
6. Repeatability and Stability Test: Repeat each test point 3 times, recording output consistency to ensure the error does not exceed the basic accuracy requirement of ±2.5%.
III. Post-Calibration Processing:
1. Record calibration data (including input speed, output signal, and response time) to generate a calibration report.
2. Affix a calibration label, indicating the calibration date and expiration date (it is recommended to calibrate every 6 months).
3. Reseal and confirm the explosion-proof seal is intact to prevent methane gas intrusion.
IV. Precautions
1. On-site calibration is strictly prohibited underground or in explosive environments; it must be completed in a safe area on the surface.
2. Do not alter intrinsically safe circuit parameters or replace non-certified components without authorization; otherwise, the explosion-proof qualification will be lost.
3. After calibration, an actual installation simulation test must be performed to ensure normal communication with the main unit (such as ZJZ-SZ(A)).
