ABB CI840 EXC3BSE022457R1 Profibus Communications Interface ，ABB Advant S800 I/0，ABB Advant-800xA  Size: 5.0" x 3.0" x 5.0" (12.7 cm x 7.6 cm x 12.7 cm) Weight: 0 lbs 9.0 oz (0.3kg).The ABB CI840 is a Fieldbus Communication Interface (FCI) module that performs operations such as signal processing, gathering of various supervision information, OSP handling, Hot Configuration In Run, HART pass-through, and configuration of I/O modules. It is part of the S800 I/O family, which is a highly flexible and modular process I/O system that communicates with parent controllers and PLCs over industry-standard field buses

The CI840 FCI is designed for redundant applications and connects to the controller by way of the PROFIBUS-DPV1 fieldbus. The module termination units to use are TU846 with redundant I/O and TU847 with non-redundant I/O. The CI840 has a communication protocol of PROFIBUS DP-V1 and is a slave that supports line and module redundancy, hot swap, and is used together with HI Controller

The CI840 is designed for redundant applications, which means that it has a built-in redundancy mechanism that ensures that the system continues to operate even if one module fails. This feature ensures that the system is always available and reduces downtime, which is a significant benefit for critical applications

In conclusion, the ABB CI840 is a Fieldbus Communication Interface (FCI) module that performs operations such as signal processing, gathering of various supervision information, OSP handling, Hot Configuration In Run, HART pass-through, and configuration of I/O modules. It is part of the S800 I/O family, which is a highly flexible and modular process I/O system that communicates with parent controllers and PLCs over industry-standard field buses. The CI840 FCI is designed for redundant applications and connects to the controller by way of the PROFIBUS-DPV1 fieldbus. It supports line and module redundancy, hot swap, and is used together with HI Controller. Although it is not RoHS 2 2011/65/EU compliant, it is still a highly flexible and modular process I/O system, and it has a built-in redundancy mechanism that ensures that the system continues to operate even if one module fails. However, there are other options available in the market, and it is essential to consider the features and benefits of each before making a decision