Pilz PZE 9 safety relay

Reason: Inconsistent dual channel input signals (such as asynchronous two safety outputs of the base unit), or one of the channels is disconnected.

handle:

Check if both channels of the output of the basic unit are closed properly.

Measure the voltage of Y1 and Y2 at the common terminal (A2) simultaneously.

Check the cable connections and terminal fastening.

6.5 Fault phenomenon: POWER LED flashes or does not light up

Reason:

The power supply voltage exceeds the tolerance (-15%/+10%). The 24V DC version allows 20.4V~26.4V; If it is below 20.4V, the module may not work reliably.

The power ripple is too large or there is a momentary drop.

Solution: Use a stable regulated power supply and check if the transformer capacity is sufficient for the AC version.

Regular Inspection and Maintenance Plan

According to EN ISO 13849 and the Machinery Directive, the effectiveness of safety functions must be regularly checked.

Frequency of required safety level inspection

SIL CL 3/PL e at least once a month

SIL CL 2/PL d at least once a year

Inspection steps:

Disconnect the input signal of the basic unit (such as opening the emergency stop button or protective door).

Confirm that the CH.1 and CH.2 LEDs of PZE 9 are turned off, and all safety contacts are disconnected (load stopped).

Restart the basic unit (reset), confirm that the safety contacts of PZE 9 are closed, and the CH LED lights up.

If the basic unit cannot be reset, it indicates that the feedback loop has detected an abnormality (possibly due to contact welding), and the above-mentioned troubleshooting should be carried out.

Annual in-depth maintenance:

Check if all terminal screws are loose (torque 0.5Nm).

Check if the fuse is intact and its specifications comply with the manual requirements.

Clean the cabinet dust and maintain heat dissipation.

Connection instance with basic unit

8.1 Cooperate with PNOZ X safety relay (dual channel no short circuit detection)

PNOZ X output terminals 13-14 are connected to Y1 and Y2 (dual channels) of PZE 9.

The feedback loop input terminals (Y1 and Y2, with different terminal numbers for different models) of PNOZ X are connected in series with Y3 and Y4 of PZE 9.

Connect A2 of PZE 9 to 0V and A1 to 24V DC.

8.2 Cooperate with PNOZmulti or safety PLC (with short circuit detection)

The two semiconductor outputs of the safety PLC (requiring cross short circuit monitoring) are directly connected to Y1 and Y2.

Due to the low resistance (<5 Ω) of semiconductor output, it meets the wiring requirements of "dual channel with short circuit detection" (Rmax=5 Ω for DC).

The feedback loop is connected according to the safety PLC manual.

8.3 Expanding Multiple PZE 9 Modules

If more than 8 safety contacts are required, can the output of one PZE 9 be used as the input of the next PZE 9? not allow. Because the input loop of PZE 9 requires a safe output from the base unit, and cannot come from the output of another expansion module (which would bypass feedback monitoring). The correct approach is for the base unit to simultaneously drive multiple PZEs 9 (parallel input), with each PZE9's feedback loop separately connected to the base unit's feedback loop (in series).

Common errors and avoidance

Auxiliary contacts are used for safety circuits: 91-92 must not be used for safety disconnection, only for indication.

Not using feedback loop: If Y1-Y2 is directly powered without connecting Y3-Y4 to the base unit, internal faults of PZE 9 cannot be detected, and the safety level will be reduced.

Excessive specification of fuse: Using a fuse larger than the recommended value may result in the inability to disconnect the contacts during welding, leading to safety failure.

The input circuit of the AC version uses a DC power supply: The AC version is designed for sine waves, and the DC power supply may not be able to detect the zero crossing point properly, resulting in the relay not closing or shaking.

Neglecting contact life: In high current applications with frequent switching, it is necessary to calculate the expected number of switches and compare them with the life chart. If necessary, larger capacity expansion modules (such as PZE 24V DC 16A version) should be selected.