Pilz PST 4 Standstill Monitor

Description

The Pilz PST 4, ID number 720300, is a safety relay designed for monitoring the standstill of 3-phase and 1-phase motors. It operates on a 24VDC supply and is a crucial component for safety applications such as guard locking until machinery has safely stopped. This unit is part of Pilz's legacy range of highly reliable safety components.

Specifications

• Manufacturer: Pilz
• Type: PST 4 24 V DC 6S4O
• ID Number: 720300
• Supply Voltage: 24 VDC
• Power Consumption: 5.5 W
• Output Contact AC15: 230 V / 5.0 A
• Output Contact DC13: 24 V / 7.0 A

Label Info

• AC1: 240 V 8.0 A
• DC1: 24 V 8.0 A
• Fuse Rating: 10 AF/6 AT

Application

This standstill monitor is ideal for use in applications requiring safe motor stop monitoring, including robotics, packaging machines, machine tools, and production lines where operator access is required after motor shutdown.

Country of Origin

Made in Germany.

CO2 Impact

Opting for this pre-owned unit saves approximately 12 kg of CO2, which is comparable to the emissions from driving a car for 60 kilometers.

Availability

This is an obsolete item, but it is available from our stock for immediate replacement of existing units. Order now from PLC2Day for expert support and fast delivery.

FAQ

What is the primary function of the Pilz PST 4 standstill monitor?

The PST 4 is a safety device used to monitor the standstill of electric motors. It ensures that a motor has completely stopped rotating before allowing access to hazardous areas, preventing accidents caused by unexpected movement.

While the modern equivalent is the PNOZ s50, a direct one-to-one replacement is not always possible. The wiring, configuration, and safety certification of the machine must be re-evaluated to ensure it meets current standards with the new device.

The PST 4 monitors the remanence voltage (back EMF) generated by the motor's windings as it slows down. Once this voltage drops below a set threshold, the relay confirms that the motor is at a standstill and enables its safety outputs.

Last Update: Friday, March 13, 2026

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