Features

– 8 channels for 0… .20 mA, 4… .20 mA, 0… .5 V or 1… .5 V d.c. single-ended unipolar inputs.

– 1 group of 8 channels isolated from ground.

– 12-bit resolution.

– Transmitter supply current limited per channel.

– HART direct communication.

AI815 Analogue Input Module

The AI815 analogue input module has 8 channels.

The module can be configured as a voltage or current www.cniacs.com input. Current and voltage signals cannot be mixed on the same I/O module.

The voltage and current inputs can withstand overvoltage or undervoltage of at least 11 VDC.

Input resistance is greater than 10 M ohms for voltage inputs and 250 ohms for current inputs.

The module distributes external HART-compatible transmitter power to each channel.

This adds a simple connection for power distribution to 2-wire or 3-wire transmitters. Transmitter power is monitored and current limited.

If an external power supply is used to power HART transmitters, the power supply must be HART-compatible.

The module cycles through self-diagnostics.

Module diagnostics include

– External power, transmitter power, and external shunt errors. These errors are reported as external channel errors.

– Analogue readback, reference voltage, internal power supply, checksum, watchdog, and memory. These errors are reported as module errors.

All eight channels are isolated from the module bus as a group. Power to the input stages is converted from the 24 V supply on the module bus.

The module has HART pass-through capability. Only point-to-point communication is supported.

Eight different types of MTUs can be used; the TU830/TU833 Extended MTU allows a three-wire connection to the device without additional terminals.

The TU810 (or TU814) Compact MTU has 24 V process voltage input terminals, but requires external terminals to distribute 24 V power to field devices.

The Extended MTUs, TU835 and TU838 provide one fuse per channel (3 A maximum) for external transmitter power.

The TU818 Compact MTU can be connected to 2-wire transmitters without external commissioning.

The TU812 Compact MTU has a D-Sub 25-pin (male) connector for process connection.

If HART is used, a shielded field cable for process connection is required.

The parameter shunt mode should be set to internal shunt when a current input is required and external shunt when a voltage input is required.