What is IEEE Std 1451.4-2004, what are its
uses and how does it work?
IEEE Std 1451.4 is a member of the IEEE 1451 family of smart
transducer standards.
Distinguishing features of IEEE 1451.4 are:
A mixed-mode communication interface (MMI), which allows digital
data and analog waveforms to alternately occupy a single connection,
with analog bandwidth not limited by sampling. Also defined
are separate data and analog connections for transducer applications
not adapted to the shared connection.
A transducer electronic data sheet (TEDS) definition, adapted
to very small memories through the use of templates and containing
identification and calibration data.
A template description language (TDL) allowing ongoing development
of templates for diverse transducer types.
A rich template collection adapting 1451.4 to large family
of transducers.
A transducer block definition allowing 1451.4 to adapt to
the 1451.1 Object Model.
IEEE Std 1451.4 allows self identification of transducers via
the internal TEDS, easing bookkeeping in large measurement arrays.
Stored sensitivity data allows data acquisition systems to standardize
automatically to the installed transducers and track the transducers.
A user field may be used to identify the transducer location in
human readable format. The mixed-mode interface allows the analog
waveform to be utilized in pristine form, without limitations
of bandwidth introduced by sampling.
For a detailed description on IEEE Std 1451.4 operation, click
here.
What are the benefits of using IEEE Std 1451.4-2004?
The IEEE 1451 family provides a set of common interfaces between
sensors or actuators, instruments and networks. With these standard
interfaces, interoperability and interchangeability of sensors
or actuators across different transducer networks are thus established.
These standards reduce the effort needed to develop networked
smart transducers. The use of IEEE 1451.4 based transducers offers
the potential for simple plug and play operation, simplifying
transducer installation and system upgrade.For transducer (sensor
or actuator) manufacturers, the need for major redesign of their
product for compatibility with a specific instrument or network
is eliminated. They can deliver products for multiple instruments
and networks based on one set of standard interfaces.
For control network vendors, the availability of a large pool
of network-compatible sensors and actuators will likely increase
the utilization of control networks, thus creating a push-pull
effort.
For system integrators, the standard interfaces will provide
a significant reduction in implementation effort.
For end users, IEEE Standard 1451.4-2004 has the potential to
significantly reduce the total life-cycle costs of the sensor
system or network, which include installation, maintenance, and
upgrade.
What is an IEEE 1451.4 manufacturer_ID?
Within a 64-bit section of the 1451.4 TEDS, called basic TEDS,
the manufacturer of the transducer is defined with a 14-bit code
called the manufacturer ID, along with manufacturer-assigned transducer
model number, model letter, model version nember and serial number.
(see IEEE Std 1451.4.2004 subclause 5.1.1, Table 2) The IEEE Registration
Authority issues the manufacturer ID, to guarantee that it is
unique to a manufacturer, and publishes the list of existing IEEE
1451.4 manufacturer ID's. Data acquisition systems may make use
of the basic TEDS, including manufacturer ID, and model number
data in determining the transducer type and the proper template
to be used in unpacking TEDS data, particularly in the case of
a transducer manufacturer choosing to use a non-IEEE, or manufacturer,
template. Do not confuse manufacturer ID and basic TEDS with URN,
as they are two separate and distinct entities.
For details on the 1451.4 manufacturer ID and Basic TEDS, click
here.
To view the IEEE listing of 1451.4 manufacturer ID codes, click
here.
To apply for an IEEE 1451.4 manufacturer ID code, click here.
What is a URN and why is it needed?
The unique registration number is a 64-bit unique identifier
contained in the memory devices, or nodes, in which IEEE 1451.4
TEDS data is stored. Because multiple nodes may be arrayed in
a multi-drop network format, to allow memory capacity to be increased,
or other functions to be added, the URN allows a number of nodes
to be individually accessed by the system. (see IEEE Std 1451.4.2004
subclause 5.4, figure 2) For details on the use of the URN in
node devices, click here.
Do not confuse the URN with manufacturer ID and basic TEDS, as
they are two separate and distinct entities.
IEEE 1451.4 transducer manufacturers using commercially available
nodes obtain a URN automatically in each node they purchase. Manufacturers
wishing to emulate the IEEE 1451.4 node function with an ASIC
or micro-controller, for example, must purchase a URN for each
node function produced. For this purpose, the IEEE Registration
Authority issues blocks of 4096 URN codes. If you are producing
nodes for use with IEEE 1451.4, and wish to purchase a block of
URN codes from IEEE-RA, click here.
What is a transducer electronic data sheet
(TEDS)?
Each of the standards in the IEEE 1451 family defines a storage
format for data pertinent to a transducer, to be stored in the
transducer. This data is called the transducer electronic data
sheet, or TEDS. In general, transducer identification and calibration
data are contained in the TEDS. In the case of IEEE 1451.4, the
memory is large enough to contain only packed numerical data,
without any units, which account for substantial memory usage
in the TEDS definitions of the other standards. A template therefore
defines the significance of the stored data in a 1451.4 transducer.
The template is resident in the system, which reads the TEDS and
unpacks the data.
For details on IEEE TEDS and templates, click here.
What is a template?
A template is a documented definition of the placement and significance
of each piece of data stored within the TEDS memory. (see IEEE
Std 1451.4.2004 subclause 5.3) The template is not contained within
the TEDS data, but the TEDS data identifies which template is
to be referenced in interpreting the TEDS data. Templates must
be accessible to the program code, which is used to write and
read the TEDS data, allowing that data to be properly packed for
writing and unpacked subsequent to reading. Templates are written
in the template description language (TDL) and contained in template
description files. The template description file is an ASCII text
file, written in TDL, and having a file name extension of .tdl.
(see IEEE Std 1451.4.2004 subclause 6.1) IEEE Standard 1451.4-2004
annex A contains several examples of the template description
file. Typically the template description file is read by an application
program which, at the same time,reads and interprets (or generates
and writes) the bits from (to) TEDS.
Who writes templates, where may they be obtained
and how may I publish one?
Templates, or more precisely template description files, may
be written by those having a transducer application not adapted
to an IEEE published template. It is advisable that the library
of IEEE templates be exhaustively investigated prior to undertaking
writing a custom template, since it contains templates adapted
to most transducer types. Using a standard template will save
considerable effort by the user. The IEEE template description
files can be found here.
Should writing a custom template be found necessary, please read
and understand Clause 7, Template Description Language, contained
in IEEE Std 1451.4-2004. Templates must be written in this language
and the rules of the standard followed. For more details on using
TDL, click here.
As described in the standard, a company or user can create templates
for use by all to whom the template description files are distributed.
A template description file may be submitted to IEEE for consideration
as IEEE template by the manufacturer who developed the template
of significant use, under the following condition:
The submitted template must have been in use for a sufficiently
long period and by a sufficient number of users to demonstrate
its effectiveness and freedom from defects.
All new templates must conform with the TDL syntax rules and
pass the syntax check program located in the TDL programmer's
start-up kit described below.
To submit a new template to the IEEE-RA for consideration, click
here.
The application form and the template description file must be
sent to the IEEE as indicated at the end of the form,for listing
as an IEEE template. Manufacturers may elect to use non-IEEE templates
for their own 1451.4 compliant products. Manufacturers choosing
to use unpublished, manufacturer templates are solely responsible
for the distribution and effective usage of these templates. All
manufacturer templates must conform with the TDL syntax and template
format guide. The format guide and TDL syntax check program are
located in the TDL start-up kit.
NOTICE: The attached software is currently undergoing BETA
testing. The software has not been verified for any particular
purpose. USE AT YOUR OWN RISK. The software is intended solely
as a tool of convenience. The software does NOT guarantee that
a given product is or will be compliant with IEEE-SA Standards
and is NOT intended to be used, explicitly or implicitly, to certify
or assure such compliance, and you shall NOT represent or imply
to others that IEEE-SA has tested, certified or otherwise approved
of any product developed through use of this software.
To download the programmer's startup kit for writing templates,
click here.
What is the template description language?
A major driving force behind the development of the IEEE 1451.4
standard was the need to minimize the amount of memory required
to store a TEDS; with a stated objective of only needing 256 bits,
although more are allowed. This requires a method of mapping the
bits in a precise fashion. This bit mapping is accomplished through
templates which are text based files written in the template description
language (TDL). The TDL is a formal language similar to programming
languages, but with considerably less looping and conditional
control. This is because the entire purpose of the language is
to map bits and not to implement general processing or mathematical
capabilities.
For details on the functionality and syntax of the TDL, click
here.
How can I obtain a manufacturer ID?
The IEEE Registration Authority issues IEEE 1451.4 manufacturer
ID numbers on a fee basis. To apply for an IEEE 1451.4 manufacturer
ID, click here.
How can I obtain an assignment of a URN Block(s)?
The IEEE Registration Authority issues IEEE 1451.4 URNs on a
fee basis, in blocks of 4,096 numbers. To apply for IEEE 1451.4
URN blocks, click here.
Note: There is a maximum of 10 assignments that can be issued
at one time.
What are the costs involved in obtaining a
manufacturer ID or URN block assignment, or in publishing a new
template? What is the method of payment?
The IEEE Registration Authority oversees the issuance of IEEE
1451.4 manufacturer ID numbers and URN blocks and keeps a current
listing of the IEEE 1451.4 template files. To cover administrative
costs, fees are charged for manufacturer ID numbers and URN blocks
and to publish new templates. Payment terms are listed with the
fees for each of these services.
To determine the fee or to obtain a manufacturer ID number, click
here.
To determine the fee or to obtain a URN block, click here.
To determine the fee or to publish a new template, click here.
How may I obtain the names and ID numbers
of those companies who own a manufacturer ID or URN block assignment?
The listings of existing IEEE 1451.4 manufacturer ID numbers
and URN blocks are available for no charge, from the IEEE Registration
Authority.
To view existing manufacturer ID numbers, click here.
There are no URN blocks assigned by the IEEE Registration Authority
at this time.
May I re-sell or distribute a segment of the
URN block after I obtain it?
The IEEE Registration Authority distributes URNs in blocks of
4,096, which is considered to be the smallest practical volume
for administration purposes, at a reasonable fee for small volume
users. IEEE-RA does not sanction the re-sale of partial URN blocks,
due to the danger of loss of uniqueness. Several divisions within
a company may share a block of URNs, however.
My company wants a second manufacturer ID
number for our new project. Can we receive one?
Manufacturers may obtain an additional manufacturer ID number
only when the original has become exhausted. A statement must
be furnished to the IEEE Registration Authority, verifying that
95% of the capacity of the original number has been used. The
manufacturer ID occupies 14 bits of a 64-bit transducer identifier
called the basic TEDS. The pool of individual transducer model
numbers available to each holder of a single manufacturer ID,
using the remaining 50 bits of the Basic TEDS as defined in IEEE
Standard 1451.4-2004, is therefore in excess of 54.5 million model
numbers. Each model may be produced up to a total in excess of
16.7 million serialized copies. By changing the version number
or version letter, as defined in the Standard, a larger total
of serialized copies of a given model may be supported. The total
number of individual units indentifiable using the IEEE Standard
1451.4-2004 basic TEDS, under a single manufacturer ID, is slightly
in excess of 9 x 1014.
What if the company address or contact information
changes after I have received the Manufacturer ID or URN Block
assignment, or have published a new template?
Please complete the information
change form. If there is a company name change due to purchase
or sale please also fax a press release or some details of the
company name change to +1 732-562-1571. The company name change
will not be uploaded to the public listing unless the press release
or details are received.
