Transducer Electronic Data Sheets (TEDS) uses an electronic chip that is integrated into a sensor. This chip contains the information that would typically be provided on a paper calibration sheet:
The integrated data sheet contains critical information such as transducer sensitivity, measured quantity, model number, and more.
Using TEDS eliminates the need to manually enter information from a calibration sheet into the software.
The TEDS equipped transducer is simply plugged into the acquisition system, and all the information is read into the software. Talk about making life easier!
Some benefits that come from using TEDS include:
Time saving: not necessary to manually type information from calibration sheet.
Error reduction: human error in relating information from calibration sheet into software is eliminated.
Information availability: It not necessary to hunt down the calibration sheet associated with a specific transducer.
Organization: for large channel count tests, it can be quite a burden to identify which transducer is plugged into each channel, find the calibration sheet for that transducer, and then type in the sensitivity. TEDS eliminates this. Simply instrument the test object, plug in the channels, and then read TEDS.
No flashlight: When a sensor is already mounted in a hard to access location, the serial number can be read directly into Simcenter Testlab software without having to shine a light into the deep recesses of a test object while craning your neck standing off balance on a….
1. Introduction to TEDS 2. TEDS in Simcenter Testlab with ICP Transducers 2.1 Plug In 2.2 Channel Setup worksheet 2.3 Reading TEDS 2.4 Back to Channel Setup 2.5 Verify TEDS was read correctly 3. TEDS in Simcenter Testlab with non-ICP Transducers 3.1 Channel Setup Visibility 3.2 Find the “Read TEDS” field 3.3 Switch from “ICP-Only” to “On” 4. Other TEDS Usage Considerations
1. Introduction to TEDS
TEDS calibration sheets conform to a template that is suited to a broad range of sensor types. This means that all critical sensor information can be input into the TEDS template. The TEDS standards are defined in the IEEE 1451 standard.
This standardized template means that any data acquisition system that is capable of reading TEDS can access this information and assign it to the relevant fields when doing data acquisition.
Some information that is contained on a TEDS:
AD or DC coupling
Some types of transducers that are TEDS compatible include:
ICP transducers like microphones, accelerometers, force transducers etc.
Charge transducers for accelerometers, microphones, etc.
Linear / Rotary variable differential transformer sensors (LVDT/RVDT)
Not every transducer is TEDS enabled. It requires an extra electronic chip for storing the information. Typically, during yearly calibration, the information on the chip is updated.
2. TEDS in Simcenter Testlab with ICP Transducers
To simplify channel setup of piezoelectric (ICP and IEPE) based transducers, it is possible to use TEDS transducers. See this forum post for more information about ICP and IEPE piezoelectric transducers.
To read the TEDS information in Simcenter Testlab, perform the following steps:
2.1 Plug In
After verifying that the transducer has TEDS enabled, plug the TEDS based transducer into the Simcenter SCADAS acquisition system as shown in Figure 1.
Figure 1: TEDS enabled microphone plugged into SCADAS XS.
Make sure the corresponding input mode of the channels are set to “ICP” in the Simcenter Testlab software.
2.2 Channel Setup worksheet
Switch to the Channel Setup worksheet. In the upper right, select the “Channel Setup” drop-down menu, and select to “Read TEDS” (Figure 2).
Figure 2: In the upper right of Channel Setup worksheet, switch from “Channel Setup” to “Read Teds”.
Now the TEDS sensor information can be read.
2.3 Reading TEDS
In the TEDS pane (Figure 3), click the “Refresh” button (1). The system will read the TEDS information in and populate the table on the left.
Figure 3: After pressing the “Refresh” button (1), highlight the TEDS channels of interest (2), and then press “Insert” (3) to accept the result.
Select the TEDS channel(s) of interest by clicking on the row number (2) on the right side of the screen. The corresponding data channels will be highlighted on the left side. Press “INSERT” button (3) to copy the TEDS calibration information from the sensor into the Channel Setup.
Note that both the destination channel (left side) and the TEDS channel (right side) must be selected for the INSERT operation to work.
It is not mandatory to read all available TEDS transducers. The menu is purposely designed to allow the user to select a subset of the available TEDS enabled sensors.
2.4 Back to Channel Setup
When finished, flip back to the “Channel Setup” view to hide the TEDS pane (Figure 4).
Figure 4: Switch back to Channel Setup view from Read TEDS view.
The default channel view will be restored.
2.5 Verify TEDS was read correctly
TEDS will fill in critical information like transducer model number, calibration sensitivity, serial number, etc (Figure 5).
Figure 5: After reading TEDS, the transducer information is updated in the Channel Setup worksheet.
Take a moment to make sure the information was read properly.
3. TEDS in Simcenter Testlab with non-ICP Transducers
By default in Simcenter Testlab, TEDS will only read on channels with the ICP mode activated. When working with non-ICP transducers, like polarized microphones or load cells, the following step should be done before using the previously outlined steps:
3.1 Channel Setup Visibility
In the Channel Setup worksheet, go to “Tools -> Channel Setup Visibility” (Figure 6).
Figure 6: Select “Tools -> Channel Setup Visibility” in the Channel Setup worksheet.
This will open the Channel Setup Visibility menu.
3.2 Find the “Read TEDS” field
In the “Channel Setup Visibility” window, find the “Read TEDS” field from the “Source field names” list on the left (Figure 7).
Figure 7: In the “Channel Setup Visibility” menu, move the “Read TEDS” field from the “Source field names” to the “Selected Fields column”.
Choose the “Add” button or the “Insert After/Before” button to move the “Read TEDS” field to the left side.
3.3 Switch from “ICP-Only” to “On”
Switch the “Read TEDS” field from “ICP-Only” to “On” as shown in Figure 8.
Figure 8: After the “Read TEDS” field has been added to the Channel Setup, switch the setting to “On” to use non-ICP transducers like polarized microphones and load cells.
Now TEDS can also be used with non-ICP transducers
4. Other TEDS Usage Considerations
There are some common-sense precautions when using TEDS to be aware of:
Bad Sensor: The sensor could go bad, but if the chip with the calibration value is not damaged, the calibration value will appear to read correctly. Even with TEDS transducers, it still good practice to use an external calibrator occasionally to verify that the sensor is working properly.
Cable length: The sensitivity entered by the sensor’s vendor is with a nominal length of the cable but many times the cables extend well beyond that nominal length and there will be voltage loss due to this. The actual sensitivity could be different!
Pressure and Humidity: The calibration value of a microphone can vary with humidity and atmospheric pressure. When the pressure and humidity are not the same as the factory calibration, the TEDS sensitivity value and actual sensitivity can be different. It is a good practice to calibrate microphones daily.