AUMA ACExC 01.2-SIL Explosion-Proof SIL Actuator Controls

AUMA ACExC 01.2-SIL explosion-proof SIL actuator controls

The AUMA ACExC 01.2-SIL is the explosion-proof version of the AC 01.2-SIL actuator controls. It is meant for premium safety requirements: SA .2 and SQ .2 actuators equipped with these controls can be used in safety-related systems up to SIL 3. The controls carry an additional SIL module that executes the safety functions. When a safety function is requested, the standard logic of the AC is bypassed and the safe SIL module acts, so the safety function always overrules normal operation. Seven Star LLC supplies AUMA products in Oman and the GCC as an independent supplier; this page helps you prepare a correct enquiry.

ACExC 01.2-SIL technical data

Safety functions of ACExC 01.2-SIL

• Safe OPENING (ESD), Safe CLOSING (ESD), Safe STOP OPEN and Safe STOP CLOSE
• Combinations of Safe STOP OPEN/CLOSE with one of the two ESD functions
• Selectable seating for safety operation: forced limit seating, forced limit seating with overload protection, forced torque seating or no seating
• Control of safety functions by wire-break-proof (low active) 24 V DC inputs
• Redundant setup for the ESD function

Applied in redundant setups (for example 1oo2), SIL 2 functions can be extended up to SIL 3. The fact that the safety module bypasses the standard logic is central: a fault in the normal control program cannot prevent the shutdown action.

Standard functions retained in ACExC 01.2-SIL

Apart from safety operation, the controls provide the AC functions: local controls with lockable selector switch, push buttons and indication lights, LCD for status and parametrisation, non-intrusive setting with the MWG magnetic transmitter, reversing contactors or thyristors, phase monitoring with automatic phase correction, 0/4 to 20 mA control, PID process controller, programmable stepping mode and fieldbus control (Profibus DP/DP-V2, Profinet, Modbus RTU, Modbus TCP, HART, Foundation Fieldbus and WirelessHART). Operation data are logged and a Bluetooth interface supports a notebook or Android tablet. The electrical connection is made by the AUMA plug/socket connector, with FOC connection for fieldbus interfaces.

Where ACExC 01.2-SIL is selected

Typical locations are emergency-shutdown valves on gas pipelines, burner management valves, process isolation valves in refineries and petrochemical plants and any valve whose failure to operate can create a hazardous event within a classified area. The ACExC marking indicates that the controls are suited for explosion-hazardous areas; the actual zones and gas groups are determined by the marking of the delivered unit and its certificate. The multi-turn SAEx/SAREx 07.2 to 16.2 and part-turn SQEx/SQREx 05.2 to 14.2 families are the usual partners for explosion-proof AC controls.

Selection checklist for ACExC 01.2-SIL

• Safety requirement specification: functions, SIL target, single or redundant architecture
• Hazardous-area zone, gas or dust group and temperature class needed
• Actuator type and size (SA .2 / SQ .2 with explosion-proof design)
• Seating mode needed for emergency action
• Supply and 24 V DC safety input arrangement
• Fieldbus protocol for the normal control path
• Ambient temperature up to +40 or +60 °C according to the version
• Documentation required: certificate, declaration of incorporation, wiring diagram

Commissioning and proof testing

Set the safety parameters under the plant safety procedure and document them. A functional test of each safety function from the safety logic solver should be carried out at commissioning and then at the interval set by the SIL calculation. Test with the actuator under real or simulated load where possible, so that seating mode, overload protection and travel time are confirmed. After any firmware or parameter change the safety functions must be re-validated.

Applications in Oman and the GCC

Explosion-proof safety controls are in demand for oil and gas gathering centres, gas processing, LNG facilities, petrochemical sites and power plant fuel systems in Oman and across the GCC. High heat is a design factor: the ambient rating of up to +40 or +60 °C depending on version should be checked against the installation location, including solar load on the housing.

ACExC 01.2-SIL compared with the standard ACExC 01.2

The standard ACExC 01.2 already offers explosion-proof controls with full functions and the option of safe end position feedback up to SIL 2 in selected configurations. The ACExC 01.2-SIL goes further: it adds the dedicated safety module, so that ESD closing or opening, safe stop and safe end position feedback are executed independently from the standard logic. If your project only needs position feedback for a safety loop, the standard ACExC may be sufficient; if the valve itself must be driven to a safe state on demand, the SIL version is the correct choice. Always align the decision with the safety requirement specification and the SIL verification of the complete loop, which also includes the valve, the logic solver and the proof test.

Note the ambient range. The ACExC 01.2-SIL page states a range from -25 °C to +40 or +60 °C, narrower on the cold side than the standard AC at -30 °C. Cold-climate projects should confirm the minimum temperature in writing.

Information to send with an RFQ

• Part number: ACExC 01.2-SIL and the actuator model
• SIL target, functions and architecture
• Zone and gas group, certificates needed
• Supply voltage and frequency, I/O and bus protocol
• Ambient temperature, quantity and delivery location

Documents and quotation

Send the part number ACExC 01.2-SIL, the application and the quantity, and Seven Star LLC will confirm which official documents are available for your configuration. Please do not rely on a general description alone: the order data, wiring diagram number and explosion-protection marking of the delivered unit are what count for engineering and commissioning.

Seven Star LLC is an independent supplier in Muscat serving customers across Oman and the GCC. Quotations are prepared against your enquiry data and are confirmed individually.