HZ172A601 by Danaher

The HZ172A601 is an electromechanical counter produced by Danaher for its Timers and Controllers series. Housed for panel installation, the unit integrates into relay logic or PLC-triggered lines to track repetitive machine events. It delivers a single-pole, double-throw contact once its wheel index reaches the preset value, supporting accurate lot control and cycle verification in automated production. An internal clutch and synchronous motor provide the required drive torque, allowing the counter to operate from a standard control voltage without sensor power conditioning.

Electrical operation begins with a supply of 120 V AC, which energizes the synchronous motor. At startup, the winding draws a motor inrush burden of 26 VA before settling to a lower load as the reverse-acting clutch engages. The clutch reaches pull-in within 50 ms, after which a holding demand of 10.5 VA keeps the counter wheel connected to the drive train. When the required pulse duration is applied, the mechanism advances at rates up to 500 counts per minute without missing pulses. Reverse clutch action allows the wheel assembly to reset electrically against the counting direction. Each step is mechanically latched to maintain count accuracy during normal operation.

The register can accumulate 40 counts before issuing its SPDT output. After the output is activated, an electric reset circuit returns all wheels to zero within 500 ms. For consistent resetting, the control line must remain de-energized for at least 80 ms, because the clutch mechanism ignores shorter off periods. Each input pulse must have an on-time of at least 40 ms to be recognized by the mechanism. Panel mounting simplifies installation alongside other 72 mm instruments, while the sealed enclosure supports ambient temperatures up to 60 °C. Because the counter relies on mechanical ratcheting, it does not require firmware or a battery, and recorded values remain visible during power interruptions.