Hardware Explanation of Meggitt VM600 MPS Mechanical Protection System

VM600 Mechanical Protection System (MPS) Hardware

VM600 Machinery Protection System (MPS) is a Vibro Meter product under Meggitt Sensing Systems ®  A set of digital equipment protection solutions in the product line, designed specifically for rotating machinery in the fields of power generation, petrochemicals, petroleum industry, and marine applications. This system is renowned for its high reliability, flexible configuration, and comprehensive monitoring capabilities, capable of real-time monitoring and protection of various mechanical parameters such as vibration, temperature, pressure, and displacement. This article will provide an in-depth analysis of the system architecture, core hardware components, functional characteristics, and installation security specifications of VM600 MPS based on its official hardware manual.

System Overview and Hardware Composition

The VM600 MPS adopts a modular design, with core hardware installed in a standard 19 inch rack, offering two height specifications: a 6U ABE04x system rack and a 1U ABE056 ultra-thin rack. The system can be flexibly configured according to application requirements, with the minimum configuration requiring only a rack, power supply, and a pair of processors/input/output cards.

The core of the system lies in several key card pairs:

MPC4/IOC4T card pair: This is the core of the system for vibration and dynamic pressure monitoring. MPC4 (mechanical protection card) is responsible for signal processing and alarm monitoring, while IOC4T (input/output card) provides sensor connection interface (screw terminal block), local relay output, and analog output. The two are tightly connected through the rack backplane, forming an inseparable functional unit. The MPC4 card is also divided into standard version, isolated circuit version, and safety (SIL) version to meet the needs of different safety level applications.

AMC8/IOC8T card pair: dedicated to monitoring quasi-static parameters such as temperature, liquid level, flow rate, etc. AMC8 (Analog Monitoring Card) supports thermocouple, RTD, and standard current/voltage signal inputs, with multi-channel processing capabilities (such as calculating average, maximum, minimum, and difference values). The IOC8T card paired with it provides sensor connection terminals and analog output.

CPUM/IOCN card pair (ABE04x rack only): As a "rack controller", it provides network functionality for the system. CPUM (Modular CPU Card) allows centralized configuration of all cards in the rack through Ethernet or serial interface, and supports Modbus TCP/RTU communication, achieving integration with the upper computer or control system. The IOCN card extends the network and serial communication interfaces.

Relay cards: including RLC16 cards that provide 16 relays and more intelligent IRC4 cards (configurable as 4 DPDT or 8 SPDT relays), used to output system alarm signals to external control circuits, perform shutdown or alarm actions.

Power supply: The ABE04x rack uses RPS6U rack power supply (with 300W and 330W improved versions), supporting single or dual power supply (redundant or parallel) configurations. The ABE056 rack uses RPS1U power supply.

These cards are interconnected and communicate through the VME bus, Tacho bus (for speed signal sharing), open collector electrode (OC) bus, and raw bus on the rack backplane, forming a collaborative whole.

Core functions and processing modes

The powerful features of VM600 MPS are reflected in its rich signal processing and monitoring modes, mainly achieved through the MPC4 card:

Broadband absolute bearing vibration monitoring: suitable for accelerometers or velocity sensors, can calculate acceleration, velocity, or displacement values, and perform various rectification calculations such as RMS and peak values. The bandwidth filtering range is from 0.1 Hz to 10 kHz.

Tracking (narrowband vibration analysis): capable of isolating and tracking specific vibration components related to speed (such as 1X, 2X), suitable for balancing and fault diagnosis of variable speed machinery.

Shaft relative vibration and gap monitoring: Use a proximity probe to simultaneously monitor the shaft vibration (AC component) and the static gap between the probe and the shaft (DC component).

Absolute shaft vibration monitoring: By vector synthesizing a relative shaft vibration signal with a bearing absolute vibration signal (converted to displacement through integration), the absolute shaft vibration value is obtained.

Position measurement: used to monitor the axial position and other quasi-static displacements of the shaft.

Smax measurement: According to the ISO 7919-1 standard, the maximum displacement of the axis trajectory is calculated using signals from two orthogonally installed proximity probes.

Eccentricity measurement: Monitor the bending degree of the shaft during low-speed rotation.

Differential expansion monitoring: Provides various methods such as journal method, double taper method, single taper method, and pendulum method to measure the relative thermal expansion between the rotor and stator in high-temperature environments.

Pressure and temperature monitoring: Supports monitoring and difference calculation of broadband dynamic pressure and quasi-static pressure/temperature.

Dual mathematical function: It can perform mathematical operations such as addition, subtraction, taking the maximum and minimum values between the processed signals of two channels.

Key points of safety and installation

The manual extensively emphasizes safety operating procedures, which must be strictly followed by any installation and maintenance personnel:

Electrical safety: There is hazardous voltage inside the VM600 rack. Installation and maintenance must be carried out by qualified electricians, and ensure that the rack is permanently and reliably grounded through the ground wire of the power cord. When performing live operations (such as hot swapping cards), it is important to be aware of the risk of electric shock on the exposed backplate.

Hot surface and burn risk: Depending on the ambient temperature and load, the top of the rack may become very hot, and it is necessary to wait for it to cool down during operation.

Heavy object risk: The rack filled with cards and power supplies is very heavy, and the heaviest power module should be removed before handling.

Static protection: When handling electronic cards, anti-static measures should be taken, such as wearing a grounded wristband, touching the grounding point, and using anti-static packaging.

Installation environment: The rack requires sufficient ventilation. When using natural convection cooling, at least 50mm (ABE04x) or 20mm (ABE056) of space should be reserved above and below the rack. It is recommended to use forced air cooling for dense installation or high temperature environments. It is recommended to install deflectors (barriers) above and below the rack to guide airflow and reduce the risk of electric shock or fire spread.

Card installation and hot plugging: The system supports "hot plugging" of cards when they are live. For networked racks, when hot swapping cards, the system will temporarily freeze the network communication of the bus segment where the card is located, and automatically restore it after the card initialization is completed. After the first installation or replacement of the card, it is necessary to configure the card using VM600 MPSx configuration software.

System monitoring and self checking

VM600 MPS has complete self-monitoring capabilities:

OK system check: Continuously monitor the DC level of each sensor input signal, compare it with the upper and lower limits set by the user, and use it to detect faults such as open circuits, short circuits, etc. in sensors, signal conditioners, or cables.

Built in testing: The MPC4 card has BITE function, and the AMC8/IOC8T card has BIST function, continuously checking the hardware status such as memory, logic, and power during power on and operation.

Status indication: Each processing card front panel has rich multi-color LED indicator lights, which clearly display the global status of the card (such as normal, configuration error, hardware failure), the validity of each channel signal, the alarm status (warning, danger), and the activation status of special functions (such as danger bypass, channel prohibition).

Summary

VM600 MPS is a rigorously designed, fully functional, and highly reliable industrial grade mechanical protection system. Its modular hardware architecture provides great configuration flexibility and can adapt to various application scenarios ranging from simple vibration monitoring to complex multi parameter comprehensive protection. The powerful signal processing capability, comprehensive system self checking, clear safety specifications, and support for networked integration make it an ideal choice for protecting critical rotating equipment, preventing catastrophic failures, and improving the safety and reliability of factory operations. For engineers engaged in equipment maintenance, status monitoring, and automation systems, a deep understanding of their hardware principles and specifications is the foundation for ensuring the correct installation, configuration, and long-term stable operation of the system.