Schmersal AZM300Z-ST-1P2P Wiring & M12 Pinout (PL e)

---

The Schmersal AZM300Z-ST-1P2P is a high-performance, RFID-coded electronic solenoid interlock, a cornerstone component in achieving modern machine safety standards. Its primary function is to prevent access to hazardous areas while machinery is in operation (guard locking) and to monitor the position of a safety guard (door monitoring). This specific model features a Guard Locking monitored (Z) function, Standard Coding (ST), and is equipped with one p-type diagnostic output (OUT) and two p-type safety outputs (Y1, Y2), making it a versatile choice for applications requiring up to Performance Level 'e' (PL e) in accordance with ISO 13849-1. Correct installation and precise wiring are not just operational necessities; they are critical to maintaining the functional safety of the entire system.

---

2. Pre-Installation Review of Technical Specifications

Before mounting and wiring the AZM300Z-ST-1P2P, the technician must confirm the component’s operational parameters against the machine's control system requirements. Misinterpreting these core specifications can lead to system failures or, critically, a reduction in the required safety performance level.

Key Technical Specification	Parameter	Technical Interpretation for Field Engineers
Safety Performance Level (PL)	Up to PL e (ISO 13849-1)	Achievable only when integrated correctly into a suitable safety control circuit.
Holding Force (Fzh)	1,000 N (Rated) / 1,150 N (Maximum)	The force the interlock can withstand before the safety guard opens. This must exceed the reaction forces of the guard to prevent defeat.
Actuator Tolerance (Longitudinal / Lateral)	± 3.5 mm (Longitudinal) / ± 2.0 mm (Lateral)	The permissible misalignment during guard closure. This high tolerance simplifies mechanical mounting significantly.
Safety Outputs (Y1, Y2)	2 x p-type digital outputs	PNP outputs that switch 24 VDC to the safety circuit when the guard is closed and locked. Requires connection to a safety controller (e.g., safety relay, safety PLC input).
Diagnostic Output (OUT)	1 x p-type digital output	Non-safety related output for signaling component status (e.g., guard open, solenoid engaged) to the standard PLC for monitoring or HMI display.
Latching Force (Switchable)	25 N / 50 N	The magnetic force that pulls the guard into the closed position. 50 N is typically used for heavy or misaligned doors.
Reaction Time (Switch-off via Actuator)	Maximum 100 ms	The time delay from the actuator being pulled out to the safety outputs disabling. Crucial for calculating the system's overall safety distance (S).
Connection Type	M12, 8-pole connector, A-coded	Standard industrial connection point. Requires a corresponding pre-wired M12 cable (e.g., Schmersal A-K8P-M12-S-G-5M).

---

3. Actuator Mounting and Mechanical Alignment: Achieving the ± Tolerance

The longevity and reliability of the AZM300 system depend heavily on the precision of the mechanical installation, specifically the alignment between the interlock body and the actuator (AZ/AZM300-B1). Field experience dictates that technicians must prioritize the following steps to leverage the device's high tolerance feature.

3.1. Mounting Position and Guard Stop Functionality

The AZM300 is designed for symmetrical mounting, suitable for both left and right-hinged doors, and for sliding guards. The interlock can be used as a mechanical end stop for the guard.

Technician's Insight: If the interlock is intended to function as the guard's end stop, technicians should select the 50 N latching force setting and mount the interlock body rigidly to the machine frame. This minimizes wear on the actuator. If the guard has its own robust mechanical stop, the 25 N latching force is often sufficient, reducing strain on the guard structure.

The actuator must be mounted on the movable guard so that, upon closure, it enters the opening of the interlock body. The RFID sensor requires the actuator to be within the 3.5 mm longitudinal and 2.0 mm lateral tolerance zones for the safety function to engage.

3.2. Adjusting the Latching Force

The solenoid interlock includes a Maltese Cross shaped cam used to adjust the internal latching force.

• Locate the Adjuster: The adjuster is usually visible on the side of the interlock head.
• Setting: Use a screwdriver or specialized tool to rotate the cam:
  • Position I: Approx. 25 N latching force.
  • Position II: Approx. 50 N latching force.

Field Decision Flowchart:

• IF the machine guard is light and free of structural vibration AND the closing force is minimal: THEN Select Position I (25 N).
• ELSE IF the machine guard is heavy OR is subject to significant vibration OR the interlock acts as the primary end stop: THEN Select Position II (50 N).

---

4. Electrical Connection and Pin Assignment (M12, 8-Pole)

The electrical integrity of the safety circuit is paramount. The AZM300Z-ST-1P2P uses a standard M12, 8-pole connector. Technicians must strictly adhere to the pin assignment to ensure correct safety function and non-safety diagnostic signaling.

4.1. M12 Pin-Out Configuration

Pin No.	Wire Color (Standard M12 Cable)	Signal Designation	Function
1	Brown	A1	Supply Voltage (+24 VDC)
2	White	X1	Safety Input 1 (Input for series-wiring)
3	Blue	A2	Ground (0 VDC)
4	Black	Y1	Safety Output 1 (PNP, to Safety Control)
5	Gray	OUT	Diagnostic Output (PNP, to Standard PLC I/O)
6	Pink	X2	Safety Input 2 (Input for series-wiring)
7	Red	Y2	Safety Output 2 (PNP, to Safety Control)
8	Yellow	IN	Solenoid Control Input (Guard Locking Control)

Connection Priority Note: The safety outputs (Y1, Y2) must be wired to a certified safety input module (e.g., a safety PLC or safety relay). The Diagnostic Output (OUT, Pin 5) must never be used for safety functions; its failure will not cause a safety shutdown.

4.2. Wiring for Solenoid Control (Guard Locking)

The solenoid function controls the locking mechanism. The specific model AZM300Z-ST-1P2P is typically a "Power to Unlock" (Guard Locking monitored) version, meaning the solenoid coil must be energized (Pin 8 HIGH) to allow the guard to be opened.

• Scenario: Machine Running/Guard Locked (Safe State)
  • Solenoid Control (Pin 8) is LOW (0 VDC). The solenoid is de-energized, locking the guard.
  • Safety Outputs (Y1, Y2) are HIGH (24 VDC), indicating the guard is closed and locked.
• Scenario: Machine Stopped/Guard Unlocked (Access Granted)
  • Solenoid Control (Pin 8) is HIGH (24 VDC) from the PLC/Safety Controller. The solenoid is energized, unlocking the guard.
  • Safety Outputs (Y1, Y2) transition to LOW (0 VDC) when the solenoid unlocks and/or the actuator is removed.

Technician's Field Check: When commissioning, always verify the solenoid's function by removing power (A1, A2) and confirming the guard remains locked. This confirms the failsafe principle of "Power to Unlock."

---

5. Series-Wiring Without Safety Degradation

One of the significant advantages of the AZM300 is its ability to be series-wired without reducing the attained safety level (PL e), provided the cable length and voltage drop are managed. This simplifies wiring on machines with multiple safety guards.

5.1. Safety Chain Series Connection

For standard series-wiring of safety components:

• Connect the Safety Outputs (Y1, Y2) of the first interlock to the Safety Inputs (X1, X2) of the second interlock.
• Repeat this pattern. The final device's outputs connect back to the safety monitoring device (e.g., the Safety Relay's input).

Series-Wiring Condition: The maximum number of devices is technically unlimited, but the overall cable length and voltage drop must be observed. The total length of the sensor chain should be limited, typically to around 200 m, to maintain sufficient voltage (>15 V) at the final safety device's inputs. A reduction in voltage below the minimum threshold (15 V) will cause an immediate safety trip.

5.2. Practical Diagnostic Series Integration

While the safety outputs are series-wired, the Diagnostic Output (OUT, Pin 5) from each interlock is typically wired individually back to the standard PLC's input rack.

Experienced Technician's Advice: When series-wiring 3 or more interlocks, using models with Serial Diagnostic (SD2P) capability can be more efficient. The SD version allows a dedicated diagnostic bus to report the status of up to 31 devices through a single gateway (e.g., Profibus or Ethernet-based), eliminating the need to run 31 separate diagnostic wires back to the PLC. However, for the specific 1P2P model with a single diagnostic output, individual wiring or parallel wiring of multiple diagnostic outputs (if permitted by the PLC) is the correct approach.

---

6. Troubleshooting During Commissioning: Interpreting the Status LEDs

The AZM300 features three multi-color LEDs to assist field technicians with diagnostics. Correct interpretation prevents unnecessary component replacement and speeds up fault finding.

6.1. LED Status Interpretation Chart

LED Color	Indication Type	Field Interpretation	Required Technician Action
Green (Steady)	Supply Voltage (UB)	24 VDC power is stable.	None. Device is powered.
Green (Flashing)	Guard closed, Lock Requested	Waiting for solenoid signal (Pin 8) to lock.	Check PLC program logic or Solenoid Control (Pin 8) wiring.
Yellow (Steady)	Actuator Inserted	Guard is closed and RFID sensor is activated.	Check Solenoid Control (Pin 8). If 0 VDC, outputs Y1/Y2 should be HIGH.
Red (Steady)	Fault/Error Occurred	Safety outputs (Y1, Y2) are disabled due to a serious fault (e.g., short circuit on output).	Isolate Power (LOTO), check wiring for short circuits, and attempt a fault reset.
Red (Flashing - Fast)	Actuator Misalignment	Actuator is outside the ± 3.5 mm / ± 2.0 mm tolerance.	Adjust the mechanical mounting of the actuator or the interlock body.

6.2. Conditional Fault Reset Procedure

When a Red (Steady) fault occurs, the safety outputs are immediately disabled. According to real-world experience, the fault often requires a specific sequence to reset:

• Condition 1 (Power Cycle Reset): For transient electrical faults, simply removing and restoring the 24 VDC supply (Pins 1 and 3) can clear the fault.
• Condition 2 (Guard/Solenoid Reset): For faults related to the guard position or solenoid:
  • Eliminate the fault cause (e.g., clear the short circuit, correct the misalignment).
  • Ensure the guard is closed and the solenoid is in a safe/locked state (Pin 8 LOW).
  • A fault may be automatically deleted upon the next release cycle (Solenoid Control Pin 8 transitions from LOW to HIGH).

---

7. Actuator Coding: Universal vs. Individual Implementation

The AZM300 series utilizes RFID technology for coding, offering a robust defense against tampering (defeating) compared to traditional mechanical interlocks. The Z-ST (Standard Coding) model, by default, is set to 'Universal Coding' (low coding level, ISO 14119).

• Universal Coding (Default Z-ST): The interlock will accept any standard actuator from the AZM300 series. This is suitable for general applications where a high degree of protection against tampering is not strictly mandated by risk assessment.
• Individual Coding (Available on other models): Requires a teaching-in process to accept only one specific actuator.

Decision Criterion for Engineers: If the risk assessment of the machine dictates a 'High' coding level according to ISO 14119 (e.g., high incentive for tampering), the AZM300Z-I1 (Individual Coding, Single Teaching) or AZM300Z-I2 (Individual Coding, Multiple Teaching) model should have been specified instead of the Z-ST. The Z-ST model should not be used where the risk analysis demands 'High' coding against foreseeable manipulation.

---

8. Post-Installation Functional Testing: Ensuring PL e Compliance

A successful installation is confirmed only after rigorous functional testing. The safety function must be verified before the machine is allowed to operate.

• Supply Voltage Check: Verify 24 VDC on Pin 1 (A1) and 0 VDC on Pin 3 (A2). Green LED should be ON.
• Guard Closed/Locked Test:
  • Close the guard. Yellow LED should be ON (Actuator Inserted).
  • Send the Lock signal (Pin 8 LOW). The solenoid should physically lock the guard.
  • Verify both Safety Outputs (Y1, Y2) on Pins 4 and 7 are HIGH (>20 VDC).
• Guard Open/Unlocked Test (Safety Response):
  • Send the Unlock signal (Pin 8 HIGH). The solenoid should unlock the guard.
  • Crucially: Open the guard and verify both Safety Outputs (Y1, Y2) on Pins 4 and 7 immediately drop to LOW (<5 VDC), triggering the safety stop circuit.
• Misalignment Tolerance Test: The technician should manually apply small forces to the guard to deliberately induce the maximum ± 3.5 mm longitudinal and ± 2.0 mm lateral misalignment (while the guard is closed but not locked). The Yellow LED should remain ON, confirming the interlock still registers the actuator position. If the Yellow LED turns OFF, the mounting is too restrictive and must be adjusted.

---

Note to Readers: This technical guide is intended solely for informational purposes and is not a substitute for the official product documentation or a certified safety professional's expertise. Proper installation and functional testing are the sole responsibility of the user, ensuring compliance with all local safety standards and regulations.

The author assumes no liability for any loss, damage, or malfunction resulting from the use or application of this information. Use is strictly at the reader's own risk.