Field service engineers require many different load cells spanning the numerous ranges necessary to calibrate their customers’ systems. They may also require the assortment to conduct a variety of force measurements for a particular testing application. The task begins when the engineer has to change the load cell which is connected to his instrument before he can continue. If the new cell is attached to the instrument, the appropriate calibration factors must be set up in the Force Transducer.
Avoiding user-error is really a major challenge with manual data entry or with requiring the engineer to select from a database of stored calibration parameters. Loading the wrong parameters, or even worse, corrupting the existing calibration data, can lead to erroneous results and costly recalibration expenses. Instrumentation that automatically identifies the burden cell being connected to it and self-installing the correct calibration information is optimal.
What is Transducer Electronic Datasheet? A Transducer Electronic Data Sheet (TEDS) stores transducer identification, calibration and correction data, and manufacturer-related information in a uniform manner. The IEEE Instrumentation and Measurement Society’s Sensor Technology Technical Committee developed the formats that include common, network-independent communication interfaces for connecting transducers to microprocessors and instrumentation systems.
With TEDS technology, data can be stored inside of a memory chip that is installed inside of a TEDS-compliant load cell. The TEDS standard is complicated. It specifies a huge number of detailed electronic data templates with a few amount of standardization. Even while using the data templates, it is really not guaranteed that different vendors of TEDS-compliant systems will interpret what data is put into the electronic templates in the same way. Moreover, it is not apparent that this calibration data that is needed within your application is going to be maintained by a certain vendor’s TEDS unit. You need to also ensure that you have a means to write the TEDS data in to the TEDS-compatible load cell, through either a TEDS-compatible instrument which has both TEDS-write and TEDS-read capabilities, or through the use of various other, likely computer based, TEDS data writing system.
For precision applications, such as calibration systems, it also need to be noted that calibration data that is certainly kept in the burden cell is the same regardless of what instrument is linked to it. Additional compensation for your Torque Transducer is not included. Matched systems in which a field service calibration group could be attaching different load cells to different instruments can present an issue.
Electro Standards Laboratories (ESL) has created the TEDS-Tag auto identification system which retains the attractive feature of self identification based in the TEDS standard but could be implemented simply on any load cell and, when linked to the ESL Model 4215 smart meter or CellMite intelligent digital signal conditioner, becomes transparent to the user. Multiple load-cell and multiple instrument matched pair calibrations will also be supported. This is often a critical advantage in precision applications such as field calibration services.
With all the TEDS-Tag system, a tiny and cheap electronic identification chip is positioned within the cable that extends through the load cell or it can be mounted in the cell housing. This chip includes a unique electronic serial number which can be read by the ESL Model 4215 or CellMite to recognize the cell. The cell will be linked to the unit as well as a standard calibration procedure is performed. The instrument automatically stores the calibration data within the unit itself along with the unique load cell identification number from the microchip. Whenever that cell is reconnected for the instrument, it automatically recognizes the cell and self-installs the correct calibration data. True plug-and-play operation is achieved. Using this system the calibration data can automatically include compensation for the particular instrument in order that high precision matched systems could be realized. Moreover, in the event the cell is transferred to another instrument, that instrument will recall the calibration data it has stored internally for your load cell. The ESL instruments can store multiple load cell calibration entries. In this way, multiple load cells can form a matched calibration set with multiple instruments.
Any load cell can be simply made right into a TEDS-Tag cell. The electronic identification chip, Dallas Semiconductor part number DS2401, is readily offered by distributors or from ESL. The chip is very small, which makes it simple to squeeze into a cable hood or cell housing.
Both the ESL Model 4215 smart strain gauge indicator and the CellMite intelligent digital signal conditioner are linked to load cells using a DB9 connector with identical pin outs. The electronic identification chip will not hinder the cell’s signals. Pin 3 of the DS2401 is not used and will be stop if desired. Simply connecting pins 1 and 2 through the DS2401 to pins 8 and 7, respectively, from the ESL DB9 connector will enable plug-and-play operation.
When using off-the-shelf load cells, it is often useful to locate the DS2401 in the hood in the cable. The cell features a permanently mounted cable that protrudes through the cell housing. At the conclusion of the cable, strip back the insulation from your individual wires and solder the wires into the DB9 connector. The DS2401 is soldered across DB9 pins 7 and 8, and fits within the connector’s hood. For a few dollars in parts and a simple cable termination procedure, you may have taken a standard load cell and transformed it right into a TEDS-Tag plug-and-play unit.
For applications in which accessibility load cell and cable is fixed, an in-line tag identification module could be simply constructed. A straight through in-line cable adapter can incorporate the DS2401 electronic tag chip. Within this application, the cable adapter is actually positioned in series with all the load cell cable before it really is plugged into the Load Sensor. It is additionally possible to utilize this technique in applications where different calibrations could be required on the same load cell. An individual may mbssap one particular load cell and instrument, but can change which calibration is auto-selected simply by changing the in-line cable adapter. Since each cable adapter includes a different tag identification chip, the ESL instrument will associate a different calibration data set with each in-line adapter. This can be useful, for instance, in case a precision 6-point linearization in the load cell is needed in 2 different operating ranges of the same load cell.