Modular automation system

The ex-proof AirLINE Ex 8650 modular electrical and pneumatic automation system from Bürkert, working in conjunction with modules from the intrinsically safe Siemens SIMATIC ET 200iSPTM system, has provided the solution in a recent North Sea project for Jiskoot an internationally recognised manufacturer and supplier of Zone 1 control, sampling and blending systems to the oil and gas industry.

Jiskoot, part of Cameron’s Measurement Systems Division, has over 30 years experience in the design, manufacture and supply of customised turnkey sampling systems to the global oil and gas sector. The company’s success in the sector is evidenced by the fact that over 60% of the world's crude oil is either valued on the basis of, or handled by, Jiskoot equipment.

In one of Jiskoot’s recent projects, the company required an electro-pneumatic actuation system for a sophisticated and compact gas sampling system that it was manufacturing. The skid was destined for use in the North Sea, controlling 3 gas samplers in a highly automated system for use on offshore oil rig. Maintainability and space were premium requirements.

The control solution for the skid needed to be able to interface and communicate with a PROFIBUS DP network, and be suitable for use within an ATEX Zone 1 Area. This zoning requirement meant that Jiskoot required a single supplier to provide the control solution - as an integrated system in a stainless steel control panel - which would then be certified for use in the hazardous area.

The requirement for single source responsibility was also important due to the location of the oil platform, in a remote area of the North Sea. This placed a premium on equipment conformity and reliability, as getting spares and/or personnel to site could be difficult, depending upon the prevailing weather conditions.

Until recently, Jiskoot’s requirement for a control cabinet that combined electrical and pneumatic devices for use in Zone 1/21 could not have been satisfied. This was due to the risk of corrosion of electrical parts, which could subsequently cause an explosion. However, Burkert’s development of its AirLINE Ex 8650 system meant that a new solution was available to Jiskoot. The AirLINE Ex 8650 system delivers substantial reductions in cabinet space, wiring, documentation and validation by combining EExia solenoid valves with modules from the intrinsically safe SIMATIC ET 200iSPTM system, and Fieldbus communications, providing users with a complete ATEX certified unit for use in zone 1/21.

The EX 8650-based solution allowed Jiskoot to collect all of the control signals generated on the sampling skid into one place within the hazardous area, and then seamlessly communicate this information back to a Siemens S7 315 PLC located in a safe area. The use of a pneumatic manifold with integrated Siemens I/O reduced the amount of wiring required and tubing on the skid; and because the PLC and remote I/O were from the same manufacturer, this ensured that there were no communication problems between the hazardous location panel and main control centre.

The system is housed in a stainless steel control panel with the ET200iSP distributed I/O system consisting of 17 off 3/2 solenoid pilot valves, 32 -off channels of digital input (from proximity switches) and 11- off channels of 4:20mA HART input for 2-wire transmitters.
The control panel collects the digital signals generated from position feedback switches on process valves, analogue input control signals generated by external pressure transmitters, temperature transmitter signals, position transmitters located on the sample collection cylinders to provide performance feedback and alarming and for the valve position confirmation, as well as sending pneumatic signals to the 17 process valves located on the skid. These signals are then fed back to a Siemens S7 315 PLC provided by Jiskoot’s client, which is sited in a safe area and acts as the Profibus DP system master. The S7 315 communicates with the ET200iSP module on the front end of the 8650 Valve + I/O assembly and also the Stahl ET316 Touch screen located in the door of the Jiskoot panel located in the door of the Jiskoot panel.

“We are delighted that such as prestigious project has allowed us to demonstrate the benefits that our integrated AirLINE EX 8560 system can provide in harsh, hazardous offshore applications, the integration provided a more dependable, maintainable and compact design that saved considerably on labour during design and building of this system” said Tony Brennan of Burkert UK. “In many applications offshore, customers go for traditional solutions, but we have demonstrated with this application, the real cost saving advantages of adopting new technologies that are fit for purpose.”

Burkert’s AirLINE Ex 8650 unit is fully Ex certified, it can, therefore, be used in explosion-hazard areas with gas or dust atmospheres. The system is particularly suited to decentralised process control tasks concerning fine chemicals, pharmaceuticals, cosmetics and oil and gas; and it can be employed anywhere where solvents, alcohol or lacquers are utilised. It can even be installed for direct factory automation: e.g. for the automatic filling of solvents, alcohol or lacquers. In these application areas, the new system is unique, as it is the only compact electro-pneumatic automation solution allowing integration of EExia pneumatic valves without additional wiring.