The MSI 420.TMC-03 is a safety control device designed as a replacement solution for the discontinued TMC 66. It emulates the original behavior of the TMC 66, allowing for simple replacement of older units. The system is based on the MSI 400 safe compact control from Leuze electronic.
Function Description
The primary function of the MSI 420.TMC-03 is to temporarily suppress the protective function of a safety sensor, a process known as muting. This is typically used when objects need to be transported through a danger zone without triggering a safety shutdown. During muting, the OSSD (Output Signal Switching Device) of the MSI 420.TMC-03 remains in the ON state even if the protective sensor is interrupted.
The muting process involves several phases:
- Muting preparation: Control signals (Control 1 and Control 2) are activated, typically from a standard PLC and a motor contactor, respectively. These signals prepare the system for muting. The MSI 420.TMC-03 checks for predefined signal changes within a maximum reaction time of 240 ms.
- Activating muting: When the first muting sensor (Start 1) is interrupted (signal goes LOW), the protective sensor is bridged, and muting becomes active.
- Interruption of the protective sensor: While the transport material occupies the first muting sensor, the protective sensor is also interrupted. Since the system is in the muting state, the safety outputs are not deactivated.
- Interruption of Start 2: At least 5 ms after Start 1 is interrupted, the second muting sensor (Start 2) is also interrupted by the transport material. During this phase, both muting sensors and the protective sensor must be occupied (LOW level). The device does not monitor the maximum time between the occupancy of Start 1 and Start 2.
- Start 1 becomes free: The transport material releases muting sensor 1 (Start 1) while the protective sensor is still interrupted. Muting continues.
- Protective sensor becomes free: Muting remains active even after the transport material releases the protective sensor.
- End of muting: The muting process ends, and the protective sensor resumes normal operation after the second muting sensor (Start 2) is no longer occupied by the pallet. This occurs when Control 1 and Control 2 signals are switched off, and Start 2 is activated (signal change from LOW to HIGH).
The device also supports an Override function, which allows transported objects to be removed if they have come to a standstill in the protective field due to power failures, emergency stops, or other similar circumstances. This function requires a LOW-HIGH-LOW transition (min. 350 ms and max. 3 s; longer or shorter pulses are ignored) at input I2, and the release output becomes HIGH if muting conditions are fulfilled.
Reactivation of muting is possible if the system has been reset to the base state. This requires Control 1 and Control 2 signals to be LOW potential, and Start 1 IN and Start 2 IN signals to be HIGH potential.
Important Technical Specifications
- Performance Level (PL): The maximum attainable performance level of the overall system is limited to PL c (ISO 13849-1).
- Safety Category: Category 2 (acc. to ISO 13849-1).
- Response Time: A total reaction time of 35.6 ms must be factored in for the response time of the MSI 420.TMC-03 (MSI 400 hardware + software functionality). Sensor and actuator response times must be considered separately.
- Safety Outputs: Semiconductor outputs with a switching power of up to 4A. If potential-free outputs are required, an additional relay must be used.
- Muting Sensors: Throughbeam or retro-reflective photoelectric sensors with activation input (PNP HIGH active) can be used.
- Protective Sensors: Must achieve at least Type 2 (acc. to 61496-2), PL c, and Category 2 (acc. to ISO 13849-1).
- Supply Voltage: Between 16.8 V and 30 V.
- Operating Modes: Four different operating modes are available, selected via wire bridges at the inputs I10, I11, I12:
- Mode 1: Start/restart interlock active; contactor monitoring inactive (I10, I11, I12 n.c.)
- Mode 2: Start/restart interlock inactive; contactor monitoring inactive (I10 -> 24V)
- Mode 3: Start/restart interlock active; contactor monitoring active (I11 -> 24V)
- Mode 4: Start/restart interlock inactive; contactor monitoring active (I12 -> 24V)
- Diagnostic Outputs: Three signal outputs for status indication:
- IQ1: "Error" signal output (active when an error is present).
- IQ2: "Safety on" signal output (active when safety outputs carry a HIGH signal).
- Q4: "Error indication" signal output (provides information on specific errors).
- LED Indicators:
- PWR/EC LED (green): Indicates voltage supply (16.8 V - 30 V).
- MS LED (green): Indicates control started.
- CV LED (orange): Indicates project verified and control started automatically.
- Memory Card: Software functionality is pre-stored on a supplied memory card. Changes to the logic program are not necessary during commissioning. If the memory card needs to be changed, it must be done by a Leuze electronic service technician or a competent person following specific instructions.
Usage Features
- Replacement Solution: Specifically designed to replace the TMC 66, ensuring 1:1 exchangeability in terms of wiring and functionality.
- Preconfigured Software: The device comes with pre-verified software functionality stored on a memory card, which automatically executes after power-up and self-test.
- No DIP Switches: Operating modes are selected via wire bridges at specific inputs, differing from the TMC 66's DIP switches.
- No 7-segment Display: Error display is implemented using three diagnostic outputs instead of a 7-segment display.
- No Muting Lamp Monitoring: The MSI 420.TMC-03 does not monitor the muting lamp, as this function is no longer stipulated in relevant standards. It provides one output (Q3) for an indicator light.
- Safety Distance Calculation: When calculating the safety distance (ISO 13855), the device's reaction time of 35.6 ms must be included.
- Commissioning: Requires careful adherence to the supplied wiring plan and commissioning steps, including checking sensor alignment and applying supply voltage. The selected operating mode must be validated by a competent person.
- Direction Monitoring: The system monitors the direction of the pallet (from the danger zone into the safe zone). An error is detected if Start 2 is not occupied before Start 1 becomes free again, terminating the muting process and activating an error message.
- Prevention of Unintentional Muting: Muting sensors must be mounted to prevent unintentional triggering by a person (e.g., by simultaneously activating sensors with a foot). The muting indicator should be visible from all sides.
- Protection against Tampering: Measures must be taken to prevent unintended initiation of permanent bridging through mechanical damage or misalignment of muting sensors.
Maintenance Features
- Regular Checks: The manual emphasizes the importance of regular checks on the protective device by competent persons. This includes checking the system in accordance with nationally applicable regulations and within specified time periods.
- Documentation: All changes made to the machine or protective device or the safety control must be recorded and checked against a checklist provided in the manual.
- Installation Integrity: Checks include ensuring the MSI 400 modules are implemented with all technical data, mounting conditions, and wiring integrity.
- Reliability of Safety Functions: Regular intervals are required to verify the reliability of safety functions, complying with all regulations and standards.
- Diagnostics Messages: The device provides diagnostic messages through flashing LEDs and dedicated outputs (IQ1, IQ2, Q4) to indicate potential errors and guide troubleshooting. For example, specific error codes indicate EDM errors, errors during Start 1 or Start 2 testing, or general muting errors, each with corresponding recommended measures.
- Service and Support: Contact information for 24-hour on-call service, hotline, and return address for repairs is provided.
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