Flowserve's proprietary rights are included in the information disclosed herein. Recipient, by accepting this document, agrees that neither this document nor the information disclosed herein nor any part thereof shall be reproduced or transferred to other
documents or used or disclosed to others for manufacturing or for any other purpose except as specifically authorized in writing by Flowserve.
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FLOWSERVE LIMITORQUE PROPRIETARY INFORMATION Flowserve’s proprietary rights are included in the information disclosed herein. Recipient, by accepting this document, agrees that neither this document nor the information disclosed herein nor any part thereof shall be reproduced or transferred to other...
This document is a Safety Manual for the Basic Limitorque™ MXa electronic actuator system with Standard Controls Package as developed for the Limitorque branded actuators that are manufactured by Flowserve Corporation. Optional printed circuit boards may be included with the basic actuator as shown in the following table. However, while the inclusion of those options will not result in a change to the Safety Integrity Level [SIL], their use will result in a slight reduction in values for some of the safety metrics as shown in sections 6 and 8.
For further details, refer to Instruction, Operation & Maintenance [IOM] manual for Limitorque MX Electronic Actuator, LMENIM2306. The latest version may be found on the Flowserve web site at www.flowserve.com.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Safety Integrity Level (SIL) The international standard IEC 61508 defines four Safety Integrity Levels (SIL) from SIL 1 to SIL 4. Each level provides an expectation for the probability of a failure on demand for a given safety function. Higher SIL values indicate higher integrity against random failure probability that a safety function will perform when required (see Table 1 for relative comparisons) and higher integrity against systemic failures.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Proof Test Period (Tpt) Full stroke test at least once per year ==> 8760 hr Based upon the extent of the proof test, failures undetected during normal operation or during PST may be uncovered during full proof test.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Safety Requirements 3.1 Monitor Relay Annunciation Any operating mode or self-detected system failure that could prevent the actuator from performing its Safety Instrumented Function on demand from the Safety Instrumented System shall cause the actuator’s monitor relay to de-energize, thus providing indication to the user via the alarm contacts on the monitor relay that the actuator may need to be serviced.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 3.6 Proof Test Interval User should perform a full stroke proof test sequence at least once per year during the mission life of the actuator. 3.7 Basic Safety Configuration Requirements Actuator should be configured and wired for emergency operation and partial stroke testing as shown in section 9.4 of this document.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 4.1 LimiGard™ LimiGard™ is at the heart of the design for safety that is integral to every Limitorque MXa and QX commercial and/or SIL-rated electric actuator. LimiGard is a patented digital command and monitoring system that employs coded signals throughout and automati- cally monitors the health of each signal to ensure that no component failure in the signal path can cause the actuator to move unexpectedly.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 4.2.2 Safety Critical User Wiring The LimiGard concept can be extended to user wiring as shown in Safety Block Diagram - Enhanced User Wiring (Figure 4.2 below) and configuring the actuator in accordance with subsection 10.5, Custom Input Mode - Momentary ESD/PSESD (Optional).
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Limitorque MXa Safety Functions 5.1 Emergency Shutdown Open (ESD-Open) A remote, external ESD signal may be applied to the actuator to move the valve to the OPEN position through predeter- mined, user-configured shutdown position, overriding existing control signals.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 5.6 Fail No-Action (Stay Put) Operation The system is designed so that any single-point failure in the microprocessor-controlled signal lines will automatically halt or prevent motor motion. We refer to this philosophy as “Fail No-Action.”...
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 MXa Safety 6.1 Basic board set Table 6.1 - PFD for MXa Actuator without PST Proof Test Interval Mission Time 1 year 3 years 5 years 10 yr 5.24 E-3 1.28 E-2 2.18 E-2...
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 In other words, using an MXa in an SIL-2 SIF will absorb 52.4% of the available bandwidth for SIL-2. In order to maintain a SIL-2 capability for the entire SIF, the total of the PFDavg values for all of the components that comprise the SIF must sum to no more than 0.01.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Partial Stroke Testing (PST) To ensure that the actuator remains ready to perform its safety function and to detect those faults that the actuator cannot discover by its automated Built-In Self-Test [BIST], it is strongly recommend that the user should perform periodic Partial Stroke Testing [PST].
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 While PST signals are in their normal state, the user may command an ESD action by momentarily asserting the ESD signal. The actuator will move the valve to its configured ESD position and keep it there until it receives an ESD release command.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 7.3.3 Digital Output (Relay Contact) Configuration Options for PST Status (S) alarm contacts configuration options include the following. 7.3.3.1 PST Active This function shall be set when PST STATUS is active. This function shall be reset when PST STATUS is configured, passed or failed.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 7.3.8 Actions Upon Successful Completion of the PST Stroke • PST status shall be set to Passed. • LCD indicates “STATUS OK.” • Any status relay that is configured as PST Completed Successfully shall assume its configured state.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 • Event: Actuator moved out of remote mode. • Actions: Actuator stops motion. LCD reports “STATUS OK.” Monitor relay de-energizes. PST status indicators set to either PST failed to reach target position in allotted time or PST failed to return to starting position in allotted time as appropriate.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Safety Instrumented System (SIS) Assessment The actuator is a type B product that is fit for function in SIS that may require Safety Integrity Levels 2 or 3. All Safety Instrumented Functions may be employed for SIL2 and SIL3 SIS (see section 5 Limitorque MXa Safety Instrumented Functions [SIF]).
Flowserve strongly recommends remote communication wiring be routed separately from line power wiring. Specifically, instrumentation wiring, including communication, analog and discrete signal signals, should be routed in conduits or raceways that are separate from power wiring. Flowserve cannot guarantee the reliability of instrumentation signaling if this recommendation is not implemented.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 9.4 PST and PST/ESD Configuration 9.4.1 Basic Configuration The basic PST/ESD configuration may be configured such that separate signals may be dedicated individually to PST and ESD functions. However, the enhanced PST and PST/ESD configuration employs redundant but logically opposite signals to enable PST and to release an ESD action.
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Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 ENTER Display: PASSWORD? Toggle the black OPEN-CLOSE knob: → OPEN (YES) → Release (Following screens assume default password = 100) [0] 0 0 Display: DIGIT 1 - OK? Toggle the black OPEN-CLOSE knob: → CLOSE (NO) → Release...
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 9.4.5 Set Up Enhanced ESD and PST NOTE: Enhanced ESD and PST is a factory-enabled option that should be purchased with the actuator. It may be added to in-service actuators but service and acquisition fees will be applied.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Emergency Shutdown (ESD) ESD signals may be applied to the actuator to override any existing command signal and send the valve to its pre- selected shutdown position, providing the actuator is in the remote mode.
• Motor thermal protection. WARNING: Disabling the motor over-temperature, valve jammed or over-torque protection features are permitted, but by doing so, the user chooses to void the Flowserve warranty and all third-party certifications, including Factory Mutual, CSA, IECex and ATEX.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 ESD (Emergency Shutdown) Overrides An external contact may be used to place the actuator in emergency shutdown mode. An ESD contact may be connected to the actuator to override existing command signals and send the valve to a predetermined position.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Failure Analysis Failure Analysis A single failure in MX, DCS or remote wiring of the OPEN or CLOSE signals could cause unexpected actuator motion if such failure could be interpreted by the MXA as a command signal.
10 years. 13.3 Estimated Repair Times Flowserve recommends users should maintain spare motors and printed circuit boards on hand to enable rapid repair of any such actuator that is discovered.
Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 Regulatory Information 15.1 Certification that adds HART network option board with up to SIL3 capable rating flowserve.com FLOWSERVE PROPRIETARY INFORMATION Use or disclosure of this information is subject to the restrictions on the title page of this document...
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Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 FLOWSERVE PROPRIETARY INFORMATION Use or disclosure of this information is subject to the restrictions on the title page of this document...
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Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 15.2 Original certification that added option boards with up to SIL3 capable rating flowserve.com FLOWSERVE PROPRIETARY INFORMATION Use or disclosure of this information is subject to the restrictions on the title page of this document...
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Limitorque MX Electronic Actuator FCD LMENIM2350-02 A4 – 05/16 15.3 Original SIL 3 capable certification for MXa actuator FLOWSERVE PROPRIETARY INFORMATION Use or disclosure of this information is subject to the restrictions on the title page of this document...
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Office A, 7th Floor, Plot No. 32A & B perform its intended function safely during its useful life. However, the purchaser or user of Flowserve products should be aware that Flowserve products might be used in numerous applications under a wide variety of industrial service conditions. Although Flowserve can (and often does) provide general guidelines, it cannot provide specific Ambit IT Parl, Ambit IT Park Road data and warnings for all possible applications.
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