Pilz PSWZ X1P static monitoring

Pilz PSWZ X1P Safety Static Monitoring Relay: A Complete Guide from Wiring Configuration to Troubleshooting

Introduction: Why is safe static monitoring necessary

In industrial machinery and equipment, the accidental start or incomplete stop of dangerous moving parts is often the main cause of safety accidents. Especially for large motors, fans, stamping equipment, etc. with inertial sliding, simply cutting off the main power supply cannot immediately eliminate the danger - the motor rotor may continue to rotate for seconds or even tens of seconds. At this point, if maintenance personnel enter the protected area too early, they may encounter serious mechanical injuries.

PSWZ X1P is a specialized safety static monitoring relay launched by PILZ company. It measures the regenerative voltage generated during the motor deceleration process through independent redundant channels, and only allows safe outputs (such as contactors) to be reconnected when the voltage is below the set threshold (static threshold). This device complies with PL e/Category 4 of EN ISO 13849-1 and SIL CL 3 level of EN IEC 62061, and is suitable for applications that require the highest safety integrity. This article will provide a detailed operation guide for on-site engineers from six aspects: installation, wiring, parameter setting, application examples, fault diagnosis, and maintenance testing.

Product Overview and Key Features

The PSWZ X1P has two main sub models, differing in response threshold range and connection terminal type (spring terminal or screw terminal). The core functions are as follows:

Redundant measurement: Two independent channels monitor the voltage between different phases of the motor winding (L1-L3 and L2-L3), with "simultaneous monitoring" between channels (maximum 7 seconds); If the time for the voltage of two channels to fall below the threshold is not consistent and exceeds the set value, a fault latch will be triggered.

Self check function: After each power on or reset, the device simulates exceeding the release value and detects an open circuit in the measurement circuit. It automatically tests the output relay and feedback loop for approximately 1.5 seconds.

Output configuration:

2 safety normally open contacts (momentary, 13-14, 23-24) - used to cut off hazardous power circuits.

1 auxiliary normally closed contact (41-42) - used for status indication, not for safety circuits.

Two semiconductor outputs: Y32 (switch status signal, high level valid) and Y35 (fault signal).

Wide voltage power supply: AC/DC 24-240V, suitable for most industrial sites worldwide.

Optional input range:

Standard type: Response threshold 20-500 mV, release value=2 x response value.

High sensitivity type: 7.5-500 mV (order ending in 777951).

High threshold type: 120-3000 mV (order ending in 777950).

Feedback loop monitoring: The Y1-Y2 terminals are used to monitor the feedback contacts of the external contactor, ensuring that the external contactor is indeed in the disconnected state before executing the safety output.

Selection key: The appropriate input range must be selected based on the residual magnetic voltage of the motor (i.e. the residual induced voltage generated by the motor winding after shutdown). The response range should cover the residual magnetic voltage, otherwise it is impossible to correctly detect stillness.

Installation and wiring

1. Mechanical installation

Installed in a control cabinet with a minimum protection level of IP54.

Install using a 35mm DIN rail and use the groove on the back of the device to insert the rail. When installing vertically, it is recommended to use fasteners (such as stoppers or end corners) to prevent slipping.

Dimensions: Width 45mm x Height 94mm x Depth 121mm (Spring Terminal Type Height 101mm).

2. Power wiring

Terminals A1 and A2: Connect 24-240V AC/DC (wide range automatic adaptation). Attention: Can there be no polarity distinction in DC? AC/DC is acceptable, but for DC, it is recommended to connect the positive pole to A1.

Power supply capacity: AC 5VA/DC 3W.

Allowable power interruption time: ≥ 20ms will cause output disconnection (safety side).

3. Input circuit (motor measurement wiring)

Select wiring method based on motor type:

Instructions for wiring methods of motor types

Three phase motor (standard) L1 → motor U phase, L2 → motor V phase, L3 → motor W phase. Two channels for measuring line voltages L1-L3 and L2-L3 are redundant with each other

Single phase AC motor L1 → motor live wire (L), L2 → motor neutral wire (N), L3 → motor neutral wire (N). In a single-phase system, the two channels are actually the same measurement point, but they still need to be electrically separated

DC motor L1 → motor positive pole, L3 → motor negative pole, L2 suspended or connected in parallel can only achieve single channel measurement, at which point the safety performance is reduced? Note that the manual does not recommend direct current, but it can be used in single-phase mode. To achieve the highest level of safety, three-phase motors are optimal

Maximum measured voltage: 690V AC/DC (600V when UL certified), frequency range 0-3kHz, suitable for variable frequency drive motors.