HZ171A601 by Danaher

The HZ171A601 is an electromechanical preset counter produced by Danaher for the Timers and Controllers series. It registers discrete sensor pulses and trips internal relay contacts once a selected count is reached, allowing machine cycles, feed lengths, or batch quantities to be stopped or advanced without manual intervention. Installed on control panels in packaging, material-handling, or textile equipment, the unit translates incoming pulses into count-based logic, making it a compact sequencing element in automated production lines.

The counter operates from a line supply of 120 VAC and uses a clutch-driven register that can follow inputs up to 500 counts per minute. Two separate output stages provide two instantaneous SPDT contacts and two delayed SPDT contacts for switching immediate and timed loads. Each pole is rated for 10 A at 120 VAC, permitting direct control of compatible solenoids or heaters. The rotary knob allows the setpoint to be adjusted up to 12 counts, after which the electromechanical mechanism resets. Count accuracy remains 100% because the motor-driven register advances only on complete input closures, while the 40 ms on and 80 ms off input windows prevent double triggering. A maintained clutch burden of 10.5 VA keeps the register engaged without placing excessive demand on the control transformer.

The clutch engages in 50 ms and releases after a reset period of 500 ms at the highest preset, establishing the permissible dwell time between production strokes. Reverse clutch operation allows the counter to step backward if a jam clears before the reset cycle finishes. The stepping motor can tolerate an inrush demand of 26 VA without tripping properly sized branch protection. Continuous operation is supported at ambient air temperatures up to 60 °C, allowing installation near heat-emitting machinery without derating. The electromechanical register retains the selected count through its physical setting, and the relay arrangement provides separate switching paths for immediate and delayed machine functions.