SZMJ-302 Speed RecorderDetailed product description：

The SZMJ-302 speed recorder is used for remote measurement of speed, recording speed, and achieving the purpose of two-point speed alarm. Its function is similar to that of the SZMJ-102.
When equipped with SZMB-3 sensors, the instrument can measure low speeds.

technical indicators
Usage conditions: The instrument works normally within the range of ambient temperature of 5~+40 ℃ and relative humidity<85%.
Basic error: The basic value error of the instrument shall not exceed ± 1% of the measurement upper limit value within the range of ambient temperature of 20 ± 2 ℃ and relative humidity<85%.
Temperature effect: When the temperature changes from 20 ± 2 ℃ to 5-40 ℃, the change in the instrument's reading should not exceed the absolute value of the basic error limit for every 10 ℃ change in temperature.
Recording error: The instrument recording error is the indication error ± 0.5%.
Additional electrical contact capacity: 220V, 1A AC, or 30V, 0.5A DC, with a set range of 10% to 90% of full scale.
Instrument power supply: 220V 50Hz AC, can work normally when the voltage changes to+10/-15% of the rated value and the frequency changes within the range of ± 5% of the rated value.
Power consumption: ≤ 12VA
Weight: Approximately 3.7 kilograms

Principle
The regulator consists of three parts: SZMB-0 (or SZMB-1) magnetic electric speed sensor, f/l converter, and EL936-01 automatic balance recording.
The measured speed is converted into frequency f by a magneto electric sensor, which is then amplified, shaped, and integrated into a constant current of 4-20 mA. The current is output to the EL936-01 recording instrument for indication, recording, and alarm output with two-point adjustable signals.