Universal Remote I/O Link
The Allen-Bradley Universal Remote I/O
Link connects the PLC and SLC processors to remote I/O
chassis and a host of intelligent devices such as operator
interfaces and ac and dc drives.
In addition to I/O, Allen-Bradley operator interfaces, ac
and dc drive systems, intelligent sensing products, Computer
Numerical Controllers (CNCs), and other devices are
compatible with this link. Some products, such as PanelView
Operator Terminals, have built in "adapter" capability,
while other products, such as the 1336 drives, require
optional "adapter" modules to put them on the link. Some
products are installed in the 1771 I/O chassis and
communicate over the chassis backplane to a Remote I/O
Adapter, which communicates to the programmable controller's
scanner. In addition, the 1784-PKTS communication interface
card lets an ISA/EISA bus PC communicate directly with
Allen-Bradley remote I/O devices.
Other companies offer products such as robotic and welding
controllers, scales, and wireless modems that are compatible
with the Universal Remote I/O Link as well. In total, there
are approximately 100 devices available that can communicate
on this link. By using these devices on the link, the user
can speed up communication and allow the devices to work
together to help improve quality while lowering integration,
maintenance, and training costs.
For distributed processing, put a PLC-5 processor in
"adapter mode" and install it in an I/O chassis where it can
monitor its own resident I/O while communicating to a
supervisory PLC-5 processor over the Universal Remote I/O
Link. SLC processors can also be distributed on the link
where they can control I/O while communicating with a
supervisory processor via a 1747 Direct Communication
For high-speed processing applications, an extended-local
I/O link is available, which provides a parallel I/O link
(the practical equivalent of processor-resident-chassis
performance for I/O modules not placed in the processor's
chassis). In addition, the Allen-Bradley ControlNet network,
which provides deterministic, repeatable transfers of
control data, is suitable for real-time, high-throughput
- Uses transceivers communicating over a
Universal Remote I/O
- Uses standard PVC twinaxial cable (cat. no. 1770-CD) as
the transmission medium.
- Uses a daisy-chain connection with a maximum length of
3,048m (10,000 ft).
- Operates at the data rates listed in Specifications. A
1/2-watt terminating resistor is required at each end of the
trunk line to eliminate reflections. Error checking is done
using standard CRC16 checks.
- Is based on the master/slave model. The controller's
scanner is the master and the I/O chassis or adapter devices
are slaves. The slave only responds when told to by the
- Provides transfer of a single unit (8, 16, or 32 bits) of
I/O image data to/from each I/O module in each I/O chassis
during each I/O scan. The size of the unit depends on the
I/O addressing density selected at the I/O chassis. It can
also provide block transfers of 64 words maximum to an
individual I/O module (except when used with the 1747-SN).
- Lets Remote I/O Scanners connect to a maximum of 32 I/O
chassis or other adapter-type devices on a single link.
Devices built to original Universal Remote I/O
specifications are compatible with those built to the new
specifications. However, if any of the devices on a link are
built to the original specifications, the limit is 16
devices on a single link. In any case, for a specific
scanner, the number of adapter-type devices is limited by
the I/O rack addressing capability of the scanner.
1/2W or 82.5W 1/2W
1/2W or 82.5W 1/2W