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The MPC4 machinery protection card is the central element in the VM600 series machinery protection system (MPS). This very versatile card is capable of measuring and monitoring up to four dynamic signal inputs and up to two speed inputs simultaneously.

The dynamic signal inputs are fully programmable and can accept signals representing acceleration, velocity and displacement (proximity), among others. On-board multichannel processing allows measurement of various physical parameters, including relative and absolute vibration, Smax, eccentricity, thrust position, absolute and differential housing expansion, displacement and dynamic pressure.

Digital processing includes digital filtering, integration or differentiation (if required), rectification (RMS, mean value, true peak or true peak-to-peak), order tracking (amplitude and phase) and measurement of the sensor-target gap.

The speed (tachometer) inputs accept signals from a variety of speed sensors, including systems based on proximity probes, magnetic pulse pickup sensors or TTL signals. Fractional tachometer ratios are also supported.

The configuration can be expressed in metric or imperial units. Alert and Danger set points are fully programmable, as are alarm time delay, hysteresis and latching. The Alert and Danger levels can also be adapted as a function of the speed or any external information.

A digital output is available internally (on the corresponding IOC4T input/output card) for each alarm level. These alarm signals can drive four local relays on the IOC4T card and/or can be routed using the VM600 rack’s Raw bus or Open Collector (OC) bus to drive relays on optional relay cards such as the RLC16 or IRC4.

The processed dynamic (vibration) signals and speed signals are available at the rear of the rack (on the front panel of the IOC4T) as analog output signals. Voltage-based (0 to 10 V) and current-based (4 to 20 mA) signals are provided. The MPC4 performs a self-test and diagnostic routine on power-up. In addition, the card’s builtin “OK system” continuously monitors the level of signals provided by a measurement chain (sensor and/or signal conditioner) and indicates any problem due to a broken transmission line, faulty sensor or signal conditioner.

An LED indicator on the MPC4 front panel indicates whether a processing or hardware error has occurred. Six additional LEDs (one per input channel) indicate whether the OK System has detected a fault and whether an alarm has occurred on the channel.

The MPC4 card is available in three versions: a “standard” version, a “separate circuits” version and a “safety” (SIL) version, all of which function as a card pair using a corresponding IOC4T input/ output card. Different versions of the MPC4 card The MPC4 card is available in different versions, including “standard”, “separate circuits” and “safety” (SIL) versions.

In addition, some versions are available with a conformal coating applied to the circuitry of the card for additional environmental protection against chemicals, dust, moisture and temperature extremes. Both the ‘standard’ version and the “safety” (SIL) versions of the MPC4 card are certified to IEC 61508 and ISO 13849, for use in functional safety contexts, such as SIL 1 in accordance with IEC 61508 and PL c in accordance with ISO 13849-1. The “standard” MPC4 card is the original version and supports all features and processing modes. The “standard” MPC4 is intended for safety systems using a VM600 rack with a limited range of cards, that is, “standard” MPC4/IOC4T card pairs and RLC16 relay cards. It has a VMEcompatible slave interface so it is software configurable via VME when there is a CPUx card acting as a rack controller in the VM600 rack. It is also software configurable via RS-232 (on the front panel of the card).

The “safety” (SIL) MPC4 card, known as the MPC4SIL, was developed to permit a wider range of installation options. Specifically, VM600 racks that also contain condition monitoring cards such as the XMx16 and relay cards such as the IRC4. To safety certify these configurations, it was necessary to ensure that the MPC4SIL is isolated from the other cards in a VM600 rack, so that there is no possibility of its configuration being inadvertently modified. Therefore, the MPC4SIL card does not include a VME-compatible slave interface, does not support the tachometer (speed) channels and does not provide all of the signal processing capabilities of the “standard” MPC4 card (see Additional specifications – for “standard” and “separate circuits” MPC4 cards only on page 9). Segregation of MPS and CMS The VM600 rack, machinery protection cards, condition monitoring cards and associated software are designed for compliance with the machinery protection system (MPS) and condition monitoring system (CMS) segregation requirements of the API 670 standard, which ensures that the functionality of the MPS does not depend on and is not compromised in any way by the operation of the CMS. So although machinery protection cards and condition monitoring cards can easily share sensor signals from measurement chains, MPC4/ IOC4T card pairs do not share any communication buses with XMx16/XIO16T condition monitoring card pairs in a VM600 rack, and MPC4/IOC4T card pairs are configured and operated using the VM600 MPSx software (while XMx16/XIO16T card pairs are configured and operated using the VibroSight® software). Applications information When used as a card pair with an IOC4T input/output card, the MPC4 is highly suitable for machinery monitoring and protection in a wide range of industrial applications. For further information on the use of MPC4/IOC4T card pairs in general, refer to the VM600 machinery protection system (MPS) hardware manual and the VM600 MPSx software manuals. For information on the use of MPC4/ IOC4T card pairs in functional safety contexts, refer to the refer to the VM600 functional safety manual. For specific applications, contact your local Meggitt representative.

Dynamic signal inputs Number of inputs : 4 per MPC4 card DC range : 0 to +20 V or 0 to −20 V AC range : ±10 V max. Common mode voltage range : −50 to +50 V CMRR : >60 dB at 50 Hz Crosstalk : −72 dB Input impedance : 200 kΩ Current input range • DC signals : 0 to 25 mA • AC signals : ±8 mA max. Analog frequency range : DC to 60 kHz (−3 dB). Note: Applicable when dynamic signal outputs are shared using the Raw bus (VM600 rack). Dynamic signal outputs can be shared with XMx16/XIO16T card pairs but cannot be shared with other MPC4/IOC4T card pairs. : Analog AC frequency range • Without integration : 0.1 Hz to 10 kHz • With integration : 2.5 Hz to 10 kHz Current measuring resistor : 324.5 Ω Buffered dynamic signal outputs The buffered “raw” dynamic signal outputs are available on the front-panel BNC connectors (MPC4 card) and the screw-terminal connectors (IOC4T card). Output impedance : 50 Ω Analog frequency range : DC to 10 kHz (−0.1 dB with a load >1 MΩ). DC to 10 kHz (−0.2 dB with a load >200 kΩ). DC to 40 kHz (−3 dB). Note: Applicable when buffered “raw” dynamic signal outputs are shared using the front-panel BNC connectors (VM600 MPC4 card) and the screw-terminal connectors (VM600 IOC4T card). Phase error : <5° (DC to 1 kHz). <30° (DC to 10 kHz). Transfer ratio • Voltage input : 1 V/V • Current input : 0.3245 V/mA