Universal Input Analog Front End with 24-Bit ADC for Industrial Process Control Systems

The AD4110-1 is a complete, single-channel, universal input analog-to-digital front end for industrial process control systems where sensor type flexibility is required.

The high voltage input is fully software configurable for current or voltage signals and allows direct interface to all standard industrial analog signal sources such as ±20 mA, ±4 mA to ±20 mA, ±10 V, and all thermocouple types. Field power can be supplied for loop powered current output sensors. A range of excitation current sources for resistance temperature detector (RTD) sensors and other resistive sensors are included. The integrated, fully differential programmable gain amplifier (PGA) offers 16 gain settings from 0.2 to 24.

The high voltage input can be programmed to power up in either voltage mode or current mode. When programmed to current mode, the unique input circuit architecture provides a path for the loop current, even in the absence of the system module power supply.

The AD4110-1 provides internal, front-end diagnostic functions to indicate overvoltage, undervoltage, open wire, overcurrent, and overtemperature conditions. The high voltage input is thermally protected, overcurrent limited, and overvoltage protected.

The AD4110-1 incorporates a precision 24-bit, Σ-Δ, analog-todigital converter (ADC) offering conversion rates from 5 SPS to 125 kSPS with simultaneous 50 Hz and 60 Hz noise rejection.

Applications

* Process control and industrial automation

* Remote and distributed control systems

* Instrumentation and measurement

* Sensor and data acquisition

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2 software programmable input terminals

* Current up to ±20 mA

* Voltage up to ±10 V

* Thermocouple

* RTD

* Replaces existing 3-terminal solutions

* Field power supply for loop powered current sensors

* HV input overvoltage protected up to ±30 V

* Internal current sense resistor

* Option to use external current sense resistor

* Current limited input even with no power supply

* Diagnostic functions for overrange and open wire detect