Upgrading Your System for Smart TEDS

Overview

Historically, when you set up and configured a measurement system, you had to manually enter important sensor parameters, such as the range, sensitivity, and scale factors, so the software would properly convert and interpret the sensor data. Now, a system outfitted with smart TEDS sensors can automate this configuration step, while also increasing the general integrity and reliability of the system.

A new standard for sensors, IEEE 1451.4, reduces the time and challenges associated with sensor configuration. The standard establishes a universally accepted method of making sensors plug-and-play, similar to the way a USB mouse is plug-and-play with a computer. IEEE 1451.4 defines a mechanism for adding self-describing behavior to sensors with an analog signal interface. This mixed-mode interface combines the traditional analog sensor signal with a low-cost, serial digital link to access a transducer electronic data sheet (TEDS) embedded in the sensor. With TEDS, the sensor identifies and describes itself to the data acquisition system to which it is connected. The smart TEDS plug-and-play technology brings a new wave of benefits to users and developers including the following:

• Quicker system startup
• Improved diagnostics
• Reduced downtime for sensor repair and replacement
• Improved asset management
• Automated use of calibration data

National Instruments LabVIEW and NI-DAQmx measurement services software have been upgraded to leverage TEDS technology by supporting Sensors Plug&Play devices. NI-DAQmx fully supports IEEE 1451.4 compliant smart TEDS sensors. TEDS reader functionality is built into Measurement & Automation Explorer (MAX), the DAQ Assistant, and the TEDS library for LabVIEW. With this new technology, you can automatically acquire sensor and TEDS related information from one or more smart TEDS sensors with the click of a mouse.

The traditional DAQ system involves a signal, transducer, signal conditioning, DAQ device, and application level software. The transducer translates a physical phenomenon (i.e. temperature, force, and position) into a digital or analog signal. This signal traverses through the signal conditioning equipment for alteration necessary for the DAQ device to read the data. The signal conditioning most commonly involves noise reduction and cancellation, filtration, amplification, excitation, and linearization. Next, the conditioned signal enters the DAQ device at which point the data is translated into digital format and passed to the computer through a variety of different bus structures. Finally, the computer software is used to analyze and present the data. Smart TEDS sensors fit into the overall picture as transducers that identify themselves with the computer automatically upon connection to the DAQ equipment. When you connect the smart TEDS sensor, information that identifies the sensor is automatically transferred through the DAQ hardware into the computer at which point the software automatically configures the sensor properties.

TEDS Smart Products - SC-2350

The National Instruments SC-2350 is a shielded carrier for SCC signal conditioning modules that features configurable connectors for Class II smart TEDS sensors. The NI SC-2350 cables directly to M Series, E Series and B Series devices, and can be powered either directly from the DAQ device or with an external power supply. IEEE 1451.4 smart TEDS sensors identify and describe themselves -- providing the manufacturer, serial number, sensitivity, calibration, and other sensor-specific information.

Upgrading from the SC-2345 series carrier is easy. After purchasing your SC-2350 TEDS-compatible chassis, simply cable the device to your 68-pin DAQ device and insert your desired signal conditioning modules.

Connect
Connect up to 16 smart TEDS sensors to the custom TEDS sensor panellettes in the SC-2350 carrier by inserting the connectors into any of the analog input sockets marked on the board. Make the proper connection from your Class II smart sensor to the TEDS compatible device. Open Measurement & Automation Explorer and add the SC-2350 chassis to your Devices & Interfaces tab. MAX will auto-detect and display all connected smart TEDS sensors.

Configure
Create an NI-DAQmx Global Channel or Task using the channel that has been associated with the TEDS sensor. Select the appropriate measurement type for your sensor and navigate the TEDS tab to choose the TEDS channel that you would like to use for this measurement. If you created a task, specify the necessary task timing (probably Continuous). Finally, name the Global Channel or Task so that you can reference it within LabVIEW.

The National Instruments BNC-2096 is a 19 in. rack-mountable BNC terminal block for NI PXI-447x, PXI-4461, and SCXI-153x modules. It provides 16 channels of Class I smart TEDS sensor inputs for sensors such as microphones and accelerometers. The NI BNC-2096 requires digital control from an NI 4021 switch controller or data acquisition device. Two or more BNC-2096 blocks can be controlled by a single device, enabling multidrop configurations for high-channel-count systems.

Connect
Make the proper connection from your Class II smart sensor to the TEDS compatible device. Open Measurement & Automation Explorer and add your BNC-2096 to the device list (Expand Devices and Interfaces by using the icon and Right-Click on NI-DAQmx Devices >> Create New NI-DAQmx Devices >> NI-DAQmx TEDS Carrier >> BNC-2096). The BNC-2096 Configuration window will appear and automatically display the connected smart TEDS sensors with green LED’s. Select the MIO device connected to the rear of the BNC-2096 as the Controlling Device.

Configure
Create an NI-DAQmx Global Channel or Task using the channel that has been associated with the TEDS sensor. Select the appropriate measurement type for your sensor and navigate the TEDS tab to choose the TEDS channel that you would like to use for this measurement. If you created a task, specify the necessary task timing (probably Continuous). Finally, name the Global Channel or Task so that you can reference it within LabVIEW.

The National Instruments SCXI-1314T is a front-mounting terminal block for the NI SCXI-1520 universal strain gauge input module. The NI SCXI-1314T includes a built-in TEDS reader for Class II bridge-based smart TEDS sensors. The terminal blocks include a socketed 100 kÙ shunt calibration resistor per channel and an RJ-50 Ethernet-style connector per channel. The 8-channel terminal block provides 10 terminals for each channel, comprised of signal+, signal-, power+, power-, remote sense+, remote sense-, shunt cal+, shunt cal-, TEDS+, and TEDS-.

Connect
Make the proper connection from your Class II smart sensor to the TEDS compatible device. Open Measurement & Automation Explorer and add your BNC-2096 to the device list (Expand Devices and Interfaces by using the icon and Right click on NI-DAQmx Devices >> Create New NI-DAQmx Devices >> NI-DAQmx SCXI Chassis >> SCXI-1000). The Create New SCXI Chassis window will appear. Select Slot 1 as the Communicating SCXI Module Slot. Ensure Chassis Address is set to 0 and that the Auto-Detect Modules in Chassis is checked. Then Click Save. Your SCXI Chassis Configuration will open. Make sure that the SCXI-1314T is listed as the accessory for your SCXI-1520 module. Click OK.
Expand the SCXI chassis using the icon and right click on the SCXI-1520 >> Configure TEDS… A Configure TEDS window will appear, and you should see the connected smart TEDS sensor and the associated channel of the SCXI module.

Configure
Create an NI-DAQmx Global Channel or Task using the channel that has been associated with the TEDS sensor. Select the appropriate measurement type for your sensor and navigate the TEDS tab to choose the TEDS channel that you would like to use for this measurement (For bridge sensors such as Load Cells, Force, Pressure, or Torque sensors, use Custom Voltage with Excitation. For Strain gauges select Strain For bridge sensors such as Load Cells, Force, Pressure, or Torque sensors, use Custom Voltage with Excitation). If you created a task, specify the necessary task timing (probably Continuous). Finally, name the Global Channel or Task so that you can reference it within LabVIEW.

Open LabVIEW. In the Block Diagram, Right-Click on the white background to bring up the functions palette. Go to All Functions >> NI Measurements >> NI-DAQmx Data Acquisition palette.
Drag the NI-DAQmx Task Name Constant and drop it on the block diagram. Move your cursor over the drop down arrow and single left click. Choose your TEDS task from the dropdown list:

Finally, Right-Click on the NI-DAQmx Task Name Constant, select Generate Code >> Configuration and Example.

Run the LabVIEW program to begin acquiring data from your Class II smart TEDS sensor.

Related Links:
Reading Smart TEDS Sensors and Virtual TEDS Files in LabVIEW
Continuous Acquisition from a Smart TEDS Load Cell Sensor
Writing to TEDS using the SC-2350
Writing to TEDS using the SCXI-1314T

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