Differences Between Class 1 and Class 2 TEDS Sensors

Updated May 25, 2022

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TEDS Sensors

Issue Details

What is the difference between Class I (Class 1) and Class II (Class 2) TEDS sensors?

Solution

Class 1 TEDS Sensor:
In Class 1 sensors, the digital signal is shared with the analog signal on the same lines and it is multiplexed based on the biasing of the sensor. The sensor includes the TEDS EEPROM and the circuitry for switching based on bias direction, which is usually only a resistor and a diode or two. Figure 1 illustrates this configuration.
Class 2 TEDS Sensor:
In Class 2 sensors, the TEDS EEPROM and analog signal use independent lines to transfer data. Due to the separate lines, no switching is needed because the digital TEDS signal and analog measurement are sent separately. Figure 2 illustrates this configuration.

Additional Information

The lists below may not be complete, always refer to the specifications to determine if your device supports TEDS.
 

Modules that support Class I (Class 1) TEDS:
NI 9218 (LEMO and DSUB Connector Type), NI 9230, NI 9232, NI 9233, NI 9234, BNC-2096, NI 446x, and NI 449x boards (except the NI 4495 (Legacy))

Modules that support Class II (Class 2) TEDS:
NI 9218 (only LEMO connector type), NI 9219, NI 9237, SCXI-1314T (Legacy) and the SC-2350 (Legacy).