An Open Electronic Marshalling Solution? Finally! - Siemens Delivers

Summary

By Bill Lydon, Editor, Automation.com

For years we have extensively covered and supported the push for open network automation solutions, and once again we are seeing some incredible innovation as a result. Most recently, Siemens introduced the first open industrial network-based electronic marshalling solution, during the 2017 Siemens Automation Summit in June in Boca Raton, Florida.  I was able to get a firsthand look at the SIMATIC Compact Field Unit (CFU) and SIMATIC ET 200SP HA products during the event and learned more about them from Stacey Jarlsberg, a Product Manager for Siemens Industry.  Given the number of vendors that have introduced electronic marshalling products, the value of electronic marshalling is clear. With Siemens’ entry into the world of open automation solutions, the value of these solutions should become increasingly clear as well.

Opening Communications with Open Protocol

Most exciting about this new offering is that it’s the first electronic marshalling product that uses a recognized open architecture industrial ethernet protocol for communications.  All the other DCS solutions available use closed protocols. Jarlsberg explained that since the Siemens solution uses standard redundant PROFINET, this enables other PROFINET devices to be easily used. Let’s take a look at how this is accomplished with the new offerings:

SIMATIC Compact Field Unit (CFU)

The SIMATIC Compact Field Unit (CFU) communicates using standard redundant PROFINET connection for the highest availability and can be configured for electrical, optical, or mixed physical network-based on requirements.   The CFU supports full redundancy, including redundant PROFINET connectivity and power supplies.

SIMATIC CFU Leverages Open Industrial Protocol – PROFINET and PROFIBUS PA

The Compact Field Unit (CFU) supports direct PROFIBUS PA integration and support of advanced PROFIBUS PA Features.  The CFU can support both PROFIBUS PA digital fieldbus devices and conventional digital signals in the same I/O. Each 16-channel standard CFU I/O module can support up to 8 channels of PROFIBUS PA. The CFU also includes several enhancements for PROFIBUS PA integration and functionality, such as automatic detection and integration of devices.  An auto-detect/auto-integrate feature is done using standard PROFIBUS PA device profiles. These provide the system with all the basic device information as well as the process value (PV).

SIMATIC ET 200SP HA

The SIMATIC ET 200SP HA is modularly designed in such a way as to use minimum space in control panels. It features a tool-free connection using push-in terminals and fixed wiring in order to cut the costs of engineering, assembly and wiring.  Its temperature range (from -40°C to +70°C) and Conformal Coating makes the SIMATIC ET 200SP HA ideally suited for field use. The desired advantages of this new technology include a Change in Run thanks to a redundant layout, and a greater number of modules on the head station, increased from 12 to 56.  The 200SP features redundant PROFINET, hot swapping modules - up to a maximum of 56 I/O modules per station - high channel density of up to 32 channels on a module,  integrated power bus, seamless integration in SIMATIC PCS 7.  The modules currently available include: 16×AI / 8×AO,  HART, 16×DI, and 16×DO.

Version 9.0 of the Simatic PCS 7 DCS

Any new devices need technical support, and that support for these devices is part of Version 9.0 of the Simatic PCS 7 DCS. This version incorporates Electronic Marshalling, along with I/O on demand, in order to simplify engineering, installation, and commissioning of systems.  Version 9.0 separates I/O hardware from software to support the “late binding” concepts, recently outlined as part of ExxonMobil’s “It Just Happens” initiative by Sandy Vasser.   The DCS itself can be developed in a virtual environment and paired with the system hardware at the last possible moment, allowing for parallel development of the system and installation and testing of the associated hardware. Version 9.0 also provides tools that simplify field device commissioning, including direct integration with PROFIBUS PA and a whole new set of PROFIBUS PA features.

Supporting Standard GSD

The software supports standard GSD (General Station Description) files which contain a description of the PROFIBUS DP/PA or PROFINET devices, as opposed to other offerings which have closed, propriety architectures.   GSD files provide a way for an open configuration to automatically get the device characteristics from any manufacturer that support PROFIBUS DP/PA or PROFINET open standards.  This benefits the entire industry, as open device profiles can significantly reduce the time needed to commission field devices. Further it can also allow for auto configuration of devices in parallel with process automation system engineering, before the actual process automation system is fully installed.  This PROFINET support at the control network - rather than a proprietary control network protocol that utilizes an Ethernet physical layer - allows the integration of a wide range of PROFINET-compliant products and components from multiple suppliers including include remote I/O, drives, network components, and other devices.

The Siemens solution is designed to reduce cost, complexity, and customization typically associated with conventional process I/O.  The single-channel I/O is assigned its type through software configuration, independent of any hardware or wiring.

Saving Time with Automatic Addressing

In another time-saving effort for the new technology, the Ethernet-based field distributor starts an initialization process in which devices are automatically addressed. The Simatic CFU automatically carries out the addressing procedure and the integration based on standard profiles, depending on the type of device used (pressure or temperature transmitter, magnetic flowmeter, etc.). These communication and device profiles are standard features of PROFIBUS PA, and thus supported by a wide range of field device suppliers. The device is then integrated in the control system and ready to operate. Siemens refers to this process as “plug-and-produce,” terminology similar to that used in process modularization approaches.

Siemens estimates that this will take significant time out of installation and can make it easier to commission digital fieldbus devices than it would be to replace conventional analog devices. Siemens believes that the device installation time can drop, from 30 minutes or more for conventional devices, down to as low as one minute for PROFIBUS PA devices.

Bill’s Thoughts & Observations

Having followed the progression of available open solutions, I believe that Siemens electronic marshaling offering is headed in the right direction and represents a leap forward for the open effort.  By tradition, DCS system architecture, segregation of functions and labor apparently required marshaling cabinets. This never made a whole lot of sense to me. In my own building automation and factory automation experience - from an engineering and applications point of view - I never felt marshaling cabinets served a great deal of purpose.   PLC systems, for years, have used remote I/O using simple interchangeable slice point modules.   The introduction of electronic marshaling, by DCS companies, has always made sense but it was always bothersome to me that they were all based on closed proprietary networking protocols.

Siemens’ initial efforts in electronic marshaling, based on industry standard open architecture protocols, is a refreshing step towards the open systems desired by so many of today’s automation users.

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