When verifying traditional analog pointer multimeters (such as the common MF47, Model 500, etc.) and new high-precision digital multimeters, metrology verifiers have distinctly different operating habits when adjusting amplitude: Analog Meters: Heavily rely on "tactile feel" — the knob needs fine adjustment to let the mechanical pointer rise slowly, until the shadow of the pointer blade precisely coincides with the reflective mirror on the dial and aligns with a major scale mark; Digital Multimeters: Operators tend to "reach the target directly" — they expect to jump quickly to the 10%, 50% or 100% full-scale points of the selected range, to check whether the digital reading changes synchronously and if there are missing segments or broken codes.

If a verification device only supports keypad input, it is very likely to encounter the awkward situation of "overshooting with one adjustment and falling short after backing off" when aligning the pointer to the scale. If only an ordinary potentiometer is available, large-span voltage rise or fall for fixed-point testing requires tedious multi-turn twisting.

To accommodate these two completely different testing habits, the HZJD8001 Multimeter Verification Device developed by Baoding Huazheng Electric Manufacturing Co., Ltd. innovatively integrates an analog plus digital dual adjustment system.

Analog Potentiometer Three-Stage Fine Adjustment, Smooth Tactile Feedback for Scale Alignment

The HZJD8001 front panel is equipped with three high-reliability non-inductive wirewound potentiometers for coarse, medium and fine adjustment: Three-speed variable adjustment: The coarse-adjustment potentiometer rapidly sets up output voltage over a wide range; the medium-adjustment potentiometer approaches the target value gently; the fine-adjustment potentiometer performs micro-step adjustment with extremely small electrical impedance steps; Effortless fine adjustment for analog meters: When verifying scales of pointer meters, rotating the fine-adjustment knob drives the pointer to move extremely smoothly and linearly, eliminating pointer jitter and mechanical impact on the hairspring caused by step jumps; Independent external control expansion box: The device supports one-click switching between internal control and external control. Verifiers can hold the lightweight external control box and operate close to the meter on the test bench, without frequently shifting sight between the main control panel and the meter under test.

Digital Step Ladder Keys, Fast Fixed-Point Adjustment at 10%/1%/0.1%/0.01%

Besides conventional analog potentiometers, four step-up keys and four step-down keys are arranged on the device panel and digital control box: Multi-range ladder setting: The four groups of keys strictly correspond to four standard weight values of 10%, 1%, 0.1% and 0.01% of full scale respectively; Smart single-tap and long-press logic: A single tap raises or lowers the output by the corresponding fixed ratio; tapping N times triggers continuous change at integer multiples. Holding the key makes the output rise steadily and continuously, and the reading locks immediately at the nearest integer-multiple standard point once the key is released; One-key gentle zero-return design: After testing, simply long-press the 10% down key for 2 to 3 seconds. The system will reduce voltage slowly at a controlled slope to zero, effectively preventing induced back EMF impact on the circuit caused by abrupt disconnection.

Combining the smooth, delicate traditional feel of knobs and the high efficiency of fixed-point stepping via keys, the HZJD8001 allows every metrology technician to work at their most comfortable operating rhythm.