ABB AI835 3BSE008520R1 Thermocouple/mV Input Module

AI835/AI835A Thermocouple/mV Input Module

Description

The AI835 Thermocouple/mV Input Module is part of the S800 I/O series. It provides 8 differential input channels for thermocouple/mV measurements. Measurement ranges configurable per channel are: -30 mV to +75 mV linear, or TC Types B, C, E, J, K, N, R, S, T.

One of the channels (Channel 8) may be configured for "Cold Junction" (ambient) temperature measurements, thus serving as the CJ-channel for channels 1 to 7. The junction temperature can be measured locally on the MTU's screw terminals or on a connection unit distant from the device. Alternatively, a fixed junction temperature for the module may be set by the user (as a parameter) or for AI835A also from the application. Channel 8 can be used in the same manner as channels 1 to 7 when no CJ-temperature measurement is needed.

Each input channel can measure an mV type of signal source (thermocouple or linear) and may be grounded or ungrounded. Full self-calibration is achieved by means of 0V, 50 mV, and 100-ohm references, which are regularly updated.

Features

• 8 differential input channels for thermocouple/mV.
• Channel 8 can be designated as the CJ-channel (4-wire Pt100 RTD).
• Supports thermocouple types: B, C, E, J, K, N, R, S, T, and for AI835A also D, L, U.
• 15-bit resolution (A/D).
• Inputs are monitored for wire-break open-circuit.

Six different types of MTUs can be used:

• TU830 (or TU833) Extended MTU
• TU810 (or TU814) Compact MTU: Enables three-wire connection to the devices without additional terminals.
• TU812 Compact MTU: Has a D-Sub 25 pin (male) connector for process connection.
• TU818 Compact MTU: Provides connection to 2-wire transmitters without external marshaling.

Shielded field cables are required for process connections.

Technical Data

General Specifications at 25°C

• Number of channels: 8 (Differential)
• Type of input: -30 mV to 75 mV linear, or TC types B, C, E, J, K, N, R, S, and T. AI835A also supports D, L, and U.
• Input impedance: > 1 MΩ
• CJ-temperature measurement reference: 4-wire connected IEC-751/Pt100 RTD, TY820 can be used
• Maximum field cable length: 600 meters (656 yd.)
• CMV between channels, max.: 12 V d.c.
• CMRR, 50 Hz, 60 Hz: 120 dB
• NMRR, 50 Hz, 60 Hz: >60 dB
• Resolution (A/D): 15 bits
• Error: 0.1%
• Temperature drift:
  • Typical: 5 ppm/°C
    
  • Max (AI835): 30 ppm/°C
• Filter, analog (1st order Low-pass): 10 Hz
• Filter (integration): 50 Hz or 60 Hz
• Update cycle time, max.:
  • 280 ms + $n \times 80$ ms at 50 Hz
  • 250 ms + $n \times 70$ ms at 60 Hz (n = active channels)
• Supervision:
  • Module: Reference channels, power supply low
  • Channel: Open-circuit
  • CJ-channel (CH8): <-40°C (-40°F) and >100°C (212°F)
• Current consumption 24 V (Modulebus): 50 mA
• Current consumption 5 V (Modulebus): 75 mA
• Power dissipation: 1.6 W

Isolation

• Groupwise isolated from ground

Mounting Termination Units

• TU810
• TU812
• TU814
• TU818
• TU830
• TU833

MTU Keying Code

• BA

Rated Insulation Voltage

• 50 V

Dielectric Test Voltage

• 500 V a.c.