ABB Ability™ System 800xA
ABB’s S400 I/O system has been
around since 1986 and created a
reputation for itself world-wide as
a capable and reliable I/O system.
But these days, spares are getting
ever harder to come by, and the
system does not support the
industry-standard field buses of
today.
Consequently ABB has developed a replacement
solution, based on its current – and future – I/O system
S800, which is designed to provide expanded
functionality, greater flexibility, higher reliability,
and improved self-diagnostics.
More specific benefits available when upgrading
from S400 I/O are:
• Retain existing field wiring, right up to their
plug-in connectors.
• Unscrew the old unit and put the new one in its
place! It will fit perfectly, down to the existing
screw holes, DIN rail and connectors.
• Pretested functionality, from the connector
sockets in.
• Shortest possible downtime. Just plug in and produce!
• Enables HART® fieldbus support and thereby
management of intelligent field devices from a
central point.
The evolution units consist of platemounted S800
I/O modules with exactly the same footprint and
mounting alternatives (corner screws or DIN rails)
as those of the old S400 units. And of plug connector
sockets and intermediate wiring that match up to the
existing field wiring and its connectors perfectly.

Table showing how S400 I/O to S800 I/O termination
units map onto existing S400 I/O installations.
Upgrading to S800 I/O is essentially as easy as re moving the existing S400 I/O station and putting
the new I/O assembly in its place.
The reward is a more capable, adaptable and main tenance-friendly I/O system that will provide reliable
service far into the future. Thereby contributing as
much as an I/O system ever can to higher output and
a better financial return.
Replaces the following S400I/O units
TU401 DSAX 452 unipolar
TU402 DSDX 452/452L/454/454L
TU403 DSDI 452/454
TU404 DSDI 452/454 + DSDI 451/453
TU405 DSDX 452/452L/454/454L + DSDI 451/453
TU406 DSDI 452/454 + DSDX 451/453
TU407 DSDX 452/452L/454/454L + DSDX 451/451L/453/453L
See product documentation for more details.