Purchase now: Allen Bradley 1747-SN RIO Scanner Module
Purchase now: Atlantechdrives provides you the 1747-SN, a critical network communication module designed by Allen Bradley for the SLC 500 automation system. As manufacturing plants expand, running thousands of individual sensor wires back to a central PLC cabinet becomes financially and logistically impossible. The 1747-SN Remote I/O (RIO) Scanner solves this by acting as a network master, allowing the SLC processor to seamlessly communicate with distributed I/O chassis, variable frequency drives, and operator interfaces located hundreds or thousands of feet away over a single «Blue Hose» cable. By managing the high-speed Universal Remote I/O link, the 1747-SN effectively extends the backplane of your SLC 500 directly onto the factory floor.
Technical Specifications of the 1747-SN
The 1747-SN occupies a single slot in the local SLC chassis and handles all the complex token-passing and error-checking of the RIO network, freeing up the CPU to focus entirely on ladder logic execution. It supports a variety of communication speeds depending on your physical cable distance requirements.
- Part Number: 1747-SN
- Module Type: Universal Remote I/O (RIO) Scanner
- Compatible System: Allen Bradley SLC 500
- Network Protocol: Allen Bradley RIO
- Maximum Logical Racks: Up to 4 logical racks per scanner
- Supported Baud Rates: 57.6 kbps, 115.2 kbps, and 230.4 kbps
- Maximum Cable Distance: 10,000 feet (at 57.6 kbps)
- Backplane Current Draw: 600 mA at 5V DC
Expert Installation Advice: The Rules of the Blue Hose
The Allen Bradley Universal Remote I/O network uses a specific 3-wire shielded twinaxial cable colloquially known as the «Blue Hose» (Belden 9463). Expert Tip: The most common reason for 1747-SN communication failures is incorrect network termination. The RIO network is a linear daisy-chain topology; you cannot use star or tree branching. At the absolute physical start of the cable (often the 1747-SN) and at the absolute physical end of the cable (the last adapter node), you must install a terminating resistor across the Line 1 and Line 2 terminals. The resistor value depends entirely on your baud rate: use a 150-ohm (1/2 watt) resistor for 57.6 kbps or 115.2 kbps, and an 82-ohm resistor for 230.4 kbps. If these are missing or mismatched, signal reflection will cause continuous dropped packets and rack faults.
Maintenance and Block Transfer Programming
Beyond discrete ON/OFF data, the 1747-SN is capable of reading complex analog values from remote racks. During maintenance or programming upgrades, engineers must remember that analog data over RIO requires the use of Block Transfer Read (BTR) and Block Transfer Write (BTW) instructions in the SLC ladder logic. These instructions map the large chunks of analog data from the remote chassis into the SLC’s integer (N) files. If an analog module on a remote rack stops responding, verify that the corresponding BTR instruction is continually being enabled by your logic scan.
Frequently Asked Questions (FAQs)
Q: Can I use the 1747-SN to communicate with a ControlLogix chassis?
A: Yes. You can put a 1756-DHRIO module in a ControlLogix chassis configured as an adapter, and the 1747-SN scanner in the SLC chassis will be able to read and write data to it via the RIO network.
Q: Does the 1747-SN support DH+ (Data Highway Plus)?
A: No. While RIO and DH+ both use the same physical «Blue Hose» cable, the protocols are completely different. The 1747-SN only speaks the RIO protocol.
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This Remote I/O scanner allows your SLC 5/03 CPU to control distributed racks across the plant floor.
