ABB AI820 Differential Analogue Input Module

Functions

- 4 channels for -20... +20 mA, 0... .20 mA,

4... .20 mA, -10... +10 V, 0...20 mA, 4...20 mA, -10... +10 V, 0... .10 V, 2... .10 V, -5... +5 V, 0... .5 V, 1... .5 V d.c. Bipolar differential inputs.

- A set of 4 channels isolated from ground.

- 14 bit resolution plus sign.

- Input shunt resistor protected to 30 VDC.

- Inputs can withstand HART communication.

AI820 Analogue Input Module

The AI820 analogue input module has 4 differential bipolar current/voltage inputs. Each

channel can be either a voltage or current input.

The current inputs are designed to withstand accidental maximum normal mode 30 VDC connections.

To protect the current input circuits from hazardous input levels (i.e., accidental connection to a 24 V power supply), the 250 Ω current-sense resistor is rated at approximately 5 watts.

This is only used for temporary protection of one channel.

The module distributes external transmitter power to each channel. This adds a simple connection (using the extended MTU) to distribute power to external 2-wire transmitters.

There is no current limit on the transmitter power terminals.

All 4 channels are isolated from a set of modular buses. Power to the input stage is converted from 24 V on the modular bus.

Four different types of MTUs can be used. the TU830 Extended MTU allows 3-wire connection to the unit without additional terminals.

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

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

Features AI820 Analogue Input Module

Number of channels 4

Input type Bipolar differential

Measuring range (nominal) -20... +20 mA, 0... .20 mA, 4... .20 mA (1)

-10... +10 V, 0... .10 V, 2... .10 V (1)

-5... +5 V, 0... .5 V, 1... .5 V (1) d.c.

Overvoltage/undervoltage range ± 15%

Input impedance (at voltage input) 200kΩ +/ - 25% Normal mode 800kΩ +/ - 25% Normal mode

Input impedance (at current input) 250 Ω

Maximum field cable length 600 metres (656 yards)

Maximum Differential DC Input (Fault) 30 VDC

Common Mode Voltage Input 50 VDC

CMRR, 50 Hz, 60 Hz 80 dB (>60 d.c.)

NMRR, 50 Hz, 60 Hz 33 dB

Maximum error 0.1%

Resolution 14 bits plus sign

Temperature drift, current 50 ppm/°C max.

Temperature drift, voltage, 70 ppm/°C max.

Update cycle time (all four channels) < 26 ms

Current consumption 24 V (module bus) 70 mA

Current consumption 5 V (module bus) 80 mA

Power dissipation 1.7 W

Voltage monitoring Internal process power supply

Input filter (rise time) 40 ms

Transmitter power fuses on extended MTUs

Isolation configuration Ground isolation

Module Terminal Unit TU810. TU812. TU814 or TU830

MTU keying code BB

Rated insulation voltage 50 V

Insulation test voltage 500 V (AC )