Precision converters simplify PLC module development

25th October 2018

Analog Devices

Alex Lynn

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Datasheet

Two multi-channel +/-10V and 0-20mA precision A/D converters that better enable implementation of programmable logic controller (PLC) and distributed control system (DCS) modules have been introduced by Analog Devices, (ADI).

Leveraging ADI’s iPassives integrated precision passives technology, the AD4111 and AD4112 A/D converters integrate precision matched current sense resistors and resistor dividers. The high degree of channel-to-channel matching simplifies calibration requirements, and with support for up to eight single-ended voltage inputs and four current inputs, makes the new products well suited for use as reconfigurable platform solutions, while reducing size, complexity and cost in PLC and DCS modules.

The AD4111 and the AD4112 A/D converters can accept +/-10V while meeting performance specifications and has a functional range of +/-20V, adding over-range margin to the nominal +/-10V. They can also accept currents of -0.5 to 24mA while meeting performance specifications. This allows reliable measurements close to 0mA and provides over range margin past 20mA.

The devices offer an Absolute Maximum Rating of +/-50V on voltage pins and +/-50mA on current pins. The AD4111 uniquely enables open wire detection, to detect when an external sensor or signal source is disconnected from the system input, on +/-10V voltage inputs while operated from either a +5V or +3.3V single power supply.

When used in conjunction with the ADuM5411 quad-channel digital isolator, the AD4111 supports EMC/EMI standards IEC 61000-2, IEC 61000-3, IEC 61000-4, IEC 61000-5, IEC 61000-6, and CISPR 11.