PLC Selection Criteria and Results

1. PLC Selection Criteria and Results David Dudley Sep 8, 2009

2. Outline • What are the PLC’s used for. • Which PLC’s were on the short list, and why. • Requirements for PLC integration. • What tests were performed. • Evaluation. • Results.

3. What are the PLC’s used for • Complete control of accelerator operations • Automatically manages control of machine operations under steady state conditions. • Controls access to accelerator facilities. • Provides the Personnel Protection System (PPS) which should prevent exposure to dangerous areas of facility. • Manages the Equipment Protection System (EPS) to prevent damage to equipment during operation. • Most actual control interfaces are linked through the PLC I/O systems.

4. What are the PLC’s used for (cont’d) • Slow and Moderate Speed I/O are linked through the PLC, which can acquire and time stamp data. • Automatic/semi-automatic or manual control of various subsystems used in the accelerator. These systems include: • Control and automatic operations of the Vacuum, RF, Power Supply, and other subsystems. • Almost all equipment monitoring. • Conventional Systems automatic control and monitoring. • HVAC monitoring.

5. What are the PLC’s used for (cont’d) • Provides secure, automatic shutdown in case of personnel intrusion into secure areas. • Protects the user from himself. • Prevents access to hazardous areas during operation. • Monitors radiation hazards in occupied areas. Should dangerous levels occur, takes protective action. • Provides for sequential systematic searching of secured areas before machine operation possible. • Enables machine to operate when all required areas are secured, and all interlocks satisfied.

6. Which PLC’s were on the short list, and why • Rockwell Automation (Allen Bradley) Control Logic and Compact Logic. • Handles Safety and Normal control systems • Fast, Compact Logix performs 1k boolean instructions in 0.08 ms, Control Logix (L63) in 0.04 ms. “Typical” instructions in 0.5ms/1k, 0.25ms/1k respectively. • Very popular in the US. • Full complement of functions. • Capable of loading/storing XML program descriptions. • Used by a great variety of customers

7. Which PLC’s were on the short list, and why • Siemens S7-300 and S7-400. • Used in a variety of control applications, including many accelerators. • Very popular in Europe. • Handles Safety and Normal control systems. • Limited text import/export capabilities. • Full complement of functions. • Fast, S7-315 performs 1k Booleans in 0.1ms, S7-317 performs in 0.05 ms, “Typical” instructions in 2 ms/1k, 0.2 ms / 1k respectively.

8. Which PLC’s were on the short list, and why • Yokogawa FA-M3 • Extremely fast. 533 Mhz Powerpc. • Very popular in Japan. • Operates as a Ladder Logic CPU (Sequence mode), or as an embedded Linux IOC. • IOC Support was developed at KEK. • Very fast, F3SP67-6S performs 1k boolean operations in 0.0175 ms, “Typical” instructions in 0.07 ms / 1k. • Handles standard EPICS record definition files.

9. Which PLC’s were on the short list, and why • GE Fanuc PACSystems RS7i. • VME64 Based. Up to a 1.8Ghz Pentium-M processor. • VME Crate chassis size would make easy integration. • Use worldwide in petrochemical, manufacturing, electrical, and pharmaceutical industry • Fast. Booleans 0.02ms/1k, “Typical” 0.03ms/1k. • All systems supported by single software package. • Software supports text input/output (degree not known).

10. Requirements for PLC Integration • All IO is to be defined through the IRMIS system. • PLC programming software MUST be able to load and store files created through the IRMIS system that defines I/O and or logic. • PLC programming must be available over ethernet. • All IOC communications to the PLCs will take place over ethernet.

11. What tests were performed • Simple interface tests to evaluate capability of PLC to integrate with EPICS. • Rockwell (A-B) EPICS response is slow, but it seems the limitations are inherent to the driver. Data size does not seem to affect transfer rate. • Siemens interface is data structure based, and requires PLC programming to build data block and send to host. • Yokogawa interface is register based, and requires a knowledge of which register number contains data required. • GE interface is Modbus based, and has same limitations as the Yokogawa interface.

12. What tests were performed • Data capture tests that evaluated acquiring/storing/timestamping 12 analog values. • Acquired data on timed basis, with one sample each 10 ms (limitation of the Siemens module used). A-B and Yokogawa were capable of performing much faster, with the A-B performing at one sample each 5 ms, and consuming 70-90 usec./cycle. Faster hardware is available as well. • Yokogawa IOC module had no problem acquiring data as fast as the scan times available would allow (0.05 sec, I believe). After additional research, the Yokogawa times could be much faster, given the speed of the hardware.

13. What tests were performed • No GE Hardware was tested. • No hardware was available, although research seems to point to the capability of very high performance from the system. • It was decided not to pursue testing with the GE equipment, due to equipment cost and other constraints.

14. What tests were performed. Additional logic for evaluation • Basic logic for First Optical Enclosure PPS Interlocks. • FOE-Permissive = TRUE when FOE is secured • Beamline Switch Permissive = TRUE when Beamline switch is in the READY position. • Rad Monitor Permissive = TRUE when Radiation within safe limits. • Safety Shutter Closed Permissive = TRUE when Photon Safety Shutter is closed and secured.

15. Siemens Ladder Logic Example • Siemens ladder logic editor equivalent of the logic becomes the following form

16. Siemens Ladder Logic Example • Exporting the ladder into a text file produces the following:

17. Siemens Import Example • Loading the text file into the ladder editor provides the following output:

18. Limitations on Siemens Import Example • Problems with the Siemens import/export file: • All symbolic information has been removed • All comment information has been removed • I/O references are to absolute locations • No tagname information has been included • Additional Text File information: • There is a text format file, which allows import/export of system configuration. The file allows complete definition of programs, and includes symbols and tags. The file format is unique, as far as I can determine, has no standard definition, and cannot be merged into existing logic.

19. Allen Bradley Ladder Logic Example • The ladder logic editor in Allen Bradley uses the same format, with the following exceptions: • Symbols are defined in the one of the Tagname tables (either Controller or Program local), and must be defined before they can be used. • Outputs are allowed inline with logic, and allow logic to continue around them.

20. Allen Bradley Logic example

21. AB XML File Example

22. Allen Bradley Text file import/export • Text file format is XML. • File format is documented (and supported) by AB. • Sample file text is included, but not shown completely. • File includes all information on controller, I/O configuration, Tagnames, and program file definitions. • Loading XML file will exactly reproduce the binary image from previous save. • Format definitions will allow a programmatic creation of complete program image. Import also allows partial file imports.

23. Yokogawa FA-M3 • Processor is comparable to the VME cards currently being used. • Module executes Linux out of a removable compact flash card. • KEK has ported the Linux IOC to the device. A driver has been written that allows direct control and communications with both the I/O hardware installed in the chassis, or a companion CPU that can run either Linux or sequential ladder logic. • Up to 4 processor modules can be installed.

24. Yokogawa FA-M3 (contd) • Sequence CPU • Logic program software is called WideField2. • Software cannot load or store any type of non-binary file describing logic operations. • Software I/O cannot be defined externally, and all logic and I/O must be defined in the software. • Software does allow a cross reference file containing tagnames (symbols) and I/O address information. • EPICS driver is available (“netdev”), however was not evaluated as I did not have access to the sequence CPU programming software.

25. Yokogawa FA-M3 • Linux CPU • IOC interfaces with I/O using Linux kernel module driver, which is closed source. • Hardware performance is outstanding, and far exceeds any of the other systems evaluated. • Hardware support includes 64 channel digital input and output modules, but analog modules are limited to 8 channels maximum. • Can directly communicate with sequence CPU installed in same chassis. • Not the desired target for reliability/flexibility.

26. GE Fanuc PacSystems RS7i • Based on VME64 Chassis. Chassis sizes vary from 10 slots to 18 slots, with both front and rear I/O access. • Supports both standard and redundant configurations. • Memory capacities from 10 Mb to 64Mb on processor card. • Capable of using high density I/O cards. • Digital inputs and outputs capable of 64 channels on a card. • Analog inputs capable of 64 channels on a card, 16 bit accuracy.

27. GE Fanuc PacSystems RS7i • I/O performance is well within requirements, exceeding the required performance for the Time stamped I/O, and providing much better analog performance in general. • Does not meet or exceed capabilities of the Yokogawa FA-M3, but exceeds capabilities of other PLCs in comparison.

28. PLC Selection Advantages/Disadvantages • Allen Bradley and GE are US Companies, and qualify for the US company incentives. • Siemens has been used successfully in a number of accelerators, including NSLS. • Yokogawa is being successfully used by KEK. • GE is known for reliability and capability worldwide. • Yokogawa can be a self-contained IOC. • AB, Siemens, and GE will all require IOC’s to communicate with EPICS.

29. PLC Selection Advantages/Disadvantages • AB directly supports complete text file configuration and programming. • It is XML standard, documented, and considered a standard program storage format. • Siemens supports text I/O and logic configuration. • Text file is custom format, and apparently not documented. • GE states they have text file capability, but have not seen it operate. • Yokogawa Sequence (LADDER) PLCs support I/O configuration through text files, but cannot accept logic using text formatted files.

30. PLC Selection Advantages/Disadvantages • Yokogawa Linux IOC supports direct control of hardware, or direct communications to Yokogawa Sequence PLC in same chassis. • Yokogawa runs IOC under Linux (advantage). • Yokogawa runs IOC under Linux (disadvantage). • All PLC units support I/O updates on “polled” or “interrupt” basis. • All PLC units (except Yokogawa IOC) must be “polled” by IOC in order to retrieve data.

31. Sample Configurations • First requirements set is based on information from Russ O’Brian and the Conventional Facilities group. • Second requirement set is based on information provided by Bob and Huijuan Vacuum control and monitoring systems. • Requirements were developed to provide unbiased design requirements for comparative analysis. These requirements take into account only the required I/O for a particular application, and not the advantages of any particular product.

32. Sample Configurations (contd) • Conventional Facilities sample. • Based on requirements for LINAC/Booster Cooling Skid, as per Russ O’Brian (6/18/09 design). • Requirements include: • CPU w/ >512k ladder logic memory. • Ethernet port. • 16 Digital Inputs. • 16 Digital Outputs. • 4 Analog Inputs (16 bit resolution). • 5 Analog RTD inputs (16 bit resolution).

33. Sample Configurations (contd) • Single PLC/Cell Storage Ring vacuum configuration. • As per Bob / Huijuan. • CPU with >1.5 Mb Ladder program space. • Ethernet Communications port. • 6 High Speed Analog Inputs with Timestamping capability. • 10 High Speed Digital Inputs with Timestamping capability. • 18 Analog Inputs. • 178 Digital Inputs. • 64 Digital Outputs. • All Analog inputs to be 16 bit accuracy.

34. Sample Configurations (contd) • Requests were sent to each vendor, to supply priced quotation for a system that met the requirement. • All documentation on each system to be available through internet, or supplied with quote from vendor. • In addition, due to high I/O count possibilities, both Yokogawa and GE were requested to provide quotes for a single system capable of providing control/monitoring for a complete cell. This included the Storage Ring, 2 Insertion Devices, and 2 Beamlines.

35. PLC Comparison Matrix

36. PLC Capabilities Comparison Chart

37. Results

38. Recommendation • 1. Limit selection to one, or two vendors. • 2. Preferred selection is Rockwell (A-B) hardware. • All levels of hardware are supported under Ethernet/IP and CIP, and allow direct access by tagname. • 3. Alternate selection is Siemens S7-300 family. • S7-200 cannot communicate with EPICS, and is unusable for anything requiring access to EPICS without substantial additional configuration and hardware/software. • S7-200 programming software has additional limitations limiting functionality. • Yokogawa has no SIL rating, and must be disqualified.