KAD/ADC/113
16 channel ¼-bridge ADC
The KAD/ADC/113 provides independent excitation for up to 16 channels and is intended for PT100 RTD type sensors. Each channel has a separate programmable digital filter and A/D converter. At the heart of the KAD/ADC/113/ET is a hard-wired state machine that oversamples all channels at a rate between 48 ksps and 96 ksps and digitally filters any noise above the user-programmable cutoff frequency. This is achieved using cascaded, half-band, Finite-Impulse-Response (FIR) filters followed by an 8th order Butterworth Infinite-Impulse-Response (IIR) filter with a default cutoff point set at one-quarter of the sampling frequency (fc = fs / 4). All signals are sampled simultaneously. Thus, when several channels are sampled at different sampling rates, at the start of an acquisition cycle all channels are aligned.
The current through the RTD is programmable from 1 mA to 2 mA in steps of 0.5 µA. The excitation current through the RTD is kept constant. As the resistance changes, the voltage across the RTD (and hence as seen by the amplifier) changes linearly.
A linearization table for each channel can be used to compensate for non-linear sensors or to fine-tune gain and offset.
- Key Features
- Applications
- Specifications
- Related Products
- 16 ¼-bridge, 3-wire, input channels for PT100 RTD-type sensors
- Input range of -200°C to 660°C
- High accuracy (0.87°C between -50 and 200°C @ 2mA)
- Programmable constant current excitation per group of four channels
- Short on any channel does not affect others
- 16-bit simultaneous sampling on each channel
- Up to 12K samples per second per channel
- Up to 3kHz Bandwidth (AAAF filter)
- Temperature measurements with RTD PT100
Resources
KAD/ADC/113
16 channel ¼-bridge ADC
The KAD/ADC/113 provides independent excitation for up to 16 channels and is intended for PT100 RTD type sensors.
