By Terry Asakawa, Japan Automation Technology Technical Committee Chapter Co-Chair, SEMI
A communication Standard which enables smarter Flow Shop type manufacturing line where:
- Material travels with its own Material Data in Object Oriented way,
- A chain of equipment executes process and coordinates Material flow in autonomous way, and
- The host controls production with equipment set up and log in indirect way.
Rationale (Targeted Areas)
SEMI A1 HC is developed as a communication protocol for smarter Flow Shop style production line to:
- reduce burden on line start-up from deficiencies in interface Standards between adjacent equipment,
- reduce overdependence on the host system which increases the cost and development time of the host, and
- improve visibility, controllability, and traceability of product.
Targeted Area of SEMI A1 HC
Purpose (Line Management Concept to be Supported)
The purpose of SEMI A1 HC is to provide communication protocol which enables the production line control concept which consists of:
- Object Oriented Material management where Material flows through a chain of equipment with its own Material Data to say who the Material is, what the Material wants to become, and how the Material has been processed.
- Autonomous process decision by equipment, feedback between equipment, and line coordination through a chain of equipment per the Work Order preset to those equipment by the host.
- Indirect production execution by the host which simply sets up equipment, watches the progress, and takes logs.
Line Management Concept which SEMI A1 HC Supports
Scope (Configuration of the Connection)
One SEMI A1 HC connection (“Line”) consists of the following two types of information channels for Horizontal Communication between adjacent equipment.
- One “Line Information” channel which performs General Data Handshake to exchange General Data to be used as commands
- Multiple “Track information” channels which perform Material Data Handshake to handoff “Material and its own Material Data” simultaneously
Line Information channel can also be used for Vertical Communication between the host and equipment as lighter protocol which conforms to PLC.
Configuration of the Connection Supported by SEMI A1 HC
Application Example in Pizza Factory Analogy
The following figure shows an application example of SEMI A1 HC in an analogy of pizza factory.
- A Pizza-to-be flows through equipment with its own Material Data supported by SEMI A1 HC. The Material Data has three categories of information; individual name, Pizza-type-to-be, and process logs at each equipment.
- On the other hand, each equipment is set its Work Order by the host. And, when a Pizza-to-be comes in, the equipment checks Pizza-type-to-be in its Material Data, looks up associated Work Order, performs the prespecified process, adds the result to the Material Data as process log, and reports the completion to the host with required logs which may be used for postmortem analysis in case.
- Also, equipment is set its line management rules from the host. And, equipment communicates with adjacent equipment by General Data supported by SEMI A1 HC and autonomously performs process feedback or flow coordination of Pizza-to-be.
- By adopting this control concept, the host simply sets up Work Order to equipment, watches the progress, and stores logs by using reports from equipment. The host won’t be bothered by Work Order communication with equipment upon each arrival of Pizza-to-be.
Application Example of SEMI A1 HC in Pizza Factory Analogy
Other Key Characteristics
SEMI A1 HC has the following key characteristics which enable smarter Flow Shop type manufacturing line.
- Direct use of TCP/IP which provides a connectivity free from industry network difference.
- Memory block transfer type of communication protocol which conforms both PC and PLC implementations.
- Material Handoff “Step” function which enables material handoff sequence with extra steps such as shield door open before handoff.
- Pause and Restart capabilities for easier operator assistance upon Material handoff jam.
- Flexible line topology which includes branch, merge, and loop.
Example of a Manufacturing Line Topology Supported by SEMI A1 HC
- Each “Track” can be configured as one of the following types; Uni-Direction (A simplex flow), Alternate Direction (Direction of flow changes upon the transfer request), or Bi-Direction (Exchange each other in one transfer sequence).
Track Types Supported by SEMI A1 HC
Please refer the following documents for detail.
- SEMI A1, Specification for Horizontal Communication Between Equipment for Factory Automation System
- Subordinate Standard: SEMI A1.1, Specification for Media Interface Specifications for a Horizontal Communication Between Equipment
SEMI Standards development activities take place throughout the year in all major manufacturing regions. To get involved, join the SEMI International Standards Program at: www.semi.org/standardsmembership.
September 21, 2017