1 BROOKHAVEN SCIENCE ASSOCIATES PLC Selection Criteria and Results David Dudley Sep 8, 2009

1 BROOKHAVEN SCIENCE ASSOCIATES

PLC Selection Criteria and Results

David DudleySep 8, 2009


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.


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.


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.


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.


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



• 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.



• 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.



• 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).


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.


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.



• 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.



• 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.


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.


Siemens Ladder Logic Example

• Siemens ladder logic editor equivalent of the logic becomes the following form


Siemens Ladder Logic Example

• Exporting the ladder into a text file produces the following:


Siemens Import Example

• Loading the text file into the ladder editor provides the following output:


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.


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.


Allen Bradley Logic example


AB XML File Example


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.


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.


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.


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.


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.


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.


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.



• 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.



• 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.


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.


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).



• 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.



• 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.


PLC Comparison MatrixPLC Manufacturer Performance

Per 1k Boolean Instructions

Time Stamping Capabilities

Fastest ADC and channel count

Network Capabilities

AB, CompactLogix 0.04ms – 0.08 ms Software supported, ~1 ms accuracy expected

4 @ .1ms/ch Yes, CIP, Ethernet are easily supported.

Siemens, S7-300 0.05 ms – 0.10 ms Hardware support, <10 ms accuracy

4 @ .1 ms/ch Yes, Profibus and Profinet require special network components

GE, RS7i 0.02 ms – 0.04 ms Hardware or Software,h/w 1ms accuracy

64 @ 1 ms/ all ch,Faster w / special VME

Yes, supports several standard Ethernet protocols

Yokogawa FA-M3Linux CPU orSequence CPU

0.02 ms – 0.04 ms Software support, EPICS compatibleSoftware support ~1 ms accuracy

4 simultaneous channels @ 50 us/48 simultaneous channels @ 500 us/8

Yes, standard EPICS channel access,Yes, but capabilities unknown.


PLC Capabilities Comparison Chart

Manufacturer and model

Memory Size

Time Stamped IO

EPICS Communications Support

Text Loads

Config#1 (Cool. Skid)

Config#2 (SR 1 Cell)

Siemens S7-300

256k - 1.4 Meg

Yes, 10ms acc.

Modbus Ladder, S7PLC

Yes, custom format

$4553.05 $9447.69

AB Control/CompactLogix

512k – 32 Meg

Yes, < 1 ms acc.

CIP, Modbus Ladder, DF1, serial

Yes, full XML file

$2650.47 $6160.41

Yokogawa FA-M3 EPICS CPU

64Meg - > 1Gb

Yes, EPICS acc

A complete EPICS IOC

Yes, EPICS

$4887.75 $6633.75

Yokagawa FA-M3 Ladder CPU

From 10k – 254k steps

Yes, < 1 ms acc.

Supported by NetDev.

At least partially, unknown

$2517.75 $4825.00

GE PacSystem RS-7i

10Meg – 64 Meg

Yes, < 1 ms acc.

Modbus, Genius, several others.

unknown $10,453.00


ResultsSelectionCriteria

Weight Rockwell(A-B)

Siemens Yokogawa GE

Customer Support 2 + Yes + Yes + Yes - Not known

Wide Hardware Selection 3 + Yes + Yes - Somewhat limited + Yes

Safety Support 3 + Yes + Yes - No + Yes

Ease of EPICS Interfacing 3 + Very, uses tagname accesses. - Possible, uses data structure and PLC software

- Yes, register number based

- Yes, register number based

TEXT import File style 3 + XML defined structure - Text file, very verbose - Only form symbols and I/O addresses

- Unknown

Text Import of Tagnames and I/O Symbols

3 + Yes + Yes + Yes - Unknown

Text Import of Program Logic 2 + Yes + Yes, very detailed - No - Unknown

TEXT import form documented and supported

2 + Yes, is standard form for import/export

- Unknown - Unknown - Unknown

Ability to merge Input files 2 + Yes, supports partial merges as well.

- No + Yes, for symbols and I/O addresses

- Unknown

Cost Comparison, Config #1 5 - 1 4 3 2+5 = 7 1

Cost Comparison, Config #2 5 - 1 4 2 3+5 = 8 1

US Company 1 + Yes - No - No + Yes

Evaluation Totals 34 +32 +18 +22 +9


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.

Documents

1 BROOKHAVEN SCIENCE ASSOCIATES PLC Selection Criteria and Results David Dudley Sep 8, 2009