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SEMI E54-0705 © SEMI 1997, 2005 5 Figure 2 Organization of SAN Specificat ion Figure 3 SAN Sta ndard R elatio nship s 7.1.1 The CDM specification is the first ancillary document of the SAN su ite. 7.1.2 A second ancillar…
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familiar with the interfaces of a large number of the SDMs. On the other hand, they will become insulated from the
inner workings of many devices, and from the code that they used to write to support those inner workings. In many
cases, they may have to implement more than one Network Communication Standard.
5.5.2 During early adoption, OEM’s may look to the SAN to act as a replacement for memory mapped discrete
wired IO. With this type of adoption, the OEM will not lessen his burden of control code.
5.5.3 As Sensor Bus becomes more broadly adopted, OEM's may take advantage of the distributed processing
capability offered by intelligent devices to reduce the complexity of their control software.
5.6 The SAN Standard Structure
5.6.1 A SAN employs devices from numerous sup-pliers. The SEMI SAN standard provides a framework to ensure
interoperability of these devices within a network. The standard enables device suppliers and equipment control
system developers to achieve that end. The SAN standard comprises five specifications.
5.6.2 The first specification is this document, which is the root document and specifies the connection between the
other documents of the standard. It also specifies the construction for each of the other documents.
5.6.3 The next specification is the Common Device Model Specification. Each device on the SAN must comply
with this specification.
5.6.4 The third specification defines the templates for creating ballots for specific device models and additions to
the NCS.
5.6.5 The fourth specification is Specific Device Models standard. These standards contain models for various types
of sensors, actuators, and entities. For instance, a model of a mass flow controller, a manometer, and a thermocouple
will be specified.
5.6.6 The fifth type of specification is the Network Communication Standards. Each network technology has its
own standard as an ancillary specification to the SAN standard.
5.6.7 Applications notes may accompany a number of the standards documents and are intended to guide
implementors in the application of the standard.
6 Concepts
6.1 Minimal device — The SAN specifications allow simple and complex devices to be built compliant to the
standard. This is done by specifying a minimum of required attributes, services, and behaviors in an SDM. The
SDMs may also provide optional service definitions that must be followed if extended capabilities are to be built
into a device. Devices that do not implement the extended capabilities must respond to extended service or access
requests with an appropriate response code rather than failing to respond or issuing an exception or alarm message.
6.2 Many of the SAN NCS specifications rely on commercial technology. A significant number of network
technologies are available off-the-shelf. The standards do not prescribe a choice. Once a technology described in an
NCS is chosen, the NCS specifies how it is to be applied. The SAN standard is easily extensible for future
technologies.
6.3 A device supplier must be able to use the standard to describe a device with little or no ambiguity for the device
users. For the user, this means that he can select a device with confidence and that it can be easily integrated with his
control system. The user must understand the electrical interface, the capabilities, and messages which a device
supports based on the supplier’s description of how this standard is supported by the device.
7 Requirements
7.1 Organization of the SAN Specifications — Figures 2 and 3 are intended to assist in understanding the document
relationships that are specified in the following subsections. In these figures, all specifications that are standards are
drawn as rounded rectangles. In Figure 3, the shadowed rectangles indicate the standards that contain requirements
for implementing devices that are compliant to this standard.
SEMI E54-0705 © SEMI 1997, 2005 5
Figure 2
Organization of SAN Specification
Figure 3
SAN Standard Relationships
7.1.1 The CDM specification is the first ancillary document of the SAN suite.
7.1.2 A second ancillary specification to the SAN standard provides templates that are guides to adding specific
device models and network communication mappings to the SAN standard.
7.1.3 Specifications for specific device models for all types of devices are included as additional ancillary
specifications of the SEMI SAN standard. Specific device models are added in the order they are developed and
passed SEMI’s ballot procedure.
7.1.4 Each network technology’s user layer specification is included as an ancillary standard (see Figure 3). These
Network Communication Standards (NCS) provide the mapping for each of the approved specific device models.
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Therefore, each NCS is also a specification that grows over time. As new device models are developed and
approved, a mapping of the model to a network technology is added to a NCS.
7.1.5 Auxiliary Information — Auxiliary information may be included with the standard in the form of appendices
or technical notes. Generally, this information is not balloted, but is included as provided by the SEMI Standards
Program regulations. Auxiliary information shall always be noted as such when it accompanies a specification or
ballot.
7.2 Interoperability
7.2.1 At the Applications Level — The SDMs are used to derive the definitions for attributes, services, and behavior
that are unique to each device type. A model may discuss relationships internal to a device to provide additional
meaning to the services and attributes that can be manipulated over the network. Applications written to these
models can operate a device independent of the network on which they communicate. The models shall assure that
devices of different types can operate cooperatively at the applications level.
7.2.2 Below the User Layer — The various SANCS specifications describe the method by which a device
communicates over a specific network such that it can meet the requirements of its type. All devices described
within an NCS shall operate cooperatively on that specific network technology below the user layer.
7.2.3 The SEMI SAN standard does not address methods for internet-working below the applications layer, as
described herein. An application entity may connect to more than one network. This could be typical of the
application entities on the equipment controller. While the SAN standard allows that application entities could exist
at any network node, it requires no mechanism for a message that begins on one network to be routed to another
network.
7.3 SEMI SAN Compliance — To fully describe the characteristics of a network capable device, its compliance
shall be specified by reference to the SAN ancillary standards. Thus, a device indicates both its type and network
technology for its SDM and a NCS.
7.3.1 For a device to be compliant to the SAN standard, it shall implement all of the required attributes, behavior,
and services as described in the SAN CDM.
7.3.2 Type or Applications Model Specification — The SDM of a device (which is its type, e.g., MFC or
thermocouple) shall be denoted by SEMI E54.y, where “y” indicates the SDM ancillary standard.
7.3.3 Network Communication Specification Communication (protocol) compliance specification of a device is
denoted by SEMI E54.x, where “x” is the network communications ancillary specification.
NOTICE: SEMI makes no warranties or representations as to the suitability of the standard set forth herein for any
particular application. The determination of the suitability of the standard is solely the responsibility of the user.
Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant
literature respecting any materials mentioned herein. These standards are subject to change without notice.
The user’s attention is called to the possibility that compliance with this standard may require use of copyrighted
material or of an invention covered by patent rights. By publication of this standard, SEMI takes no position
respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this
standard. Users of this standard are expressly advised that determination of any such patent rights or copyrights, and
the risk of infringement of such rights, are entirely their own responsibility.