1734-AENT New Original AB 1734AENT Ethernet Adapter Module
Allen-Bradley 1734-AENT | POINT I/O EtherNet/IP Adapter
Part Number: 1734-AENT
Manufacturer: Allen-Bradley / Rockwell Automation (USA)
Product Type: EtherNet/IP Communication Adapter — POINT I/O Series
Product Family: 1734 POINT I/O
Input Voltage: 24V DC nominal (10-28.8V DC range)
Overview
The 1734-AENT is the EtherNet/IP adapter for Allen-Bradley's 1734 POINT I/O system — the module that bridges a POINT I/O rack to a ControlLogix, CompactLogix, or any other EtherNet/IP-capable controller.
Install it at the leftmost position of a POINT I/O rail, connect the RJ45 Ethernet cable, and the entire I/O rack becomes a networked node that the controller can address, read, and write in real time.
The POINT I/O system itself is a dense, modular I/O platform — individual I/O modules are just 12mm wide, allowing high-density I/O in compact panel space.
Each module slides onto the DIN rail and connects to the next via the POINTBus backplane on the back of the assembly, with the 1734-AENT at the head translating between the POINTBus and the Ethernet network.
The adapter can support up to 63 POINT I/O modules in a single node — up to 504 combined I/O points — making a single 1734-AENT capable of managing a substantial portion of a machine's I/O with just one network address.
What makes the 1734-AENT a versatile field device is the combination of the CIP (Common Industrial Protocol) application layer with standard EtherNet/IP physical transport.
CIP is the same protocol layer used on ControlNet and DeviceNet, so Logix controllers communicate with POINT I/O modules through the 1734-AENT using the same programming paradigm as other CIP devices — no special communication protocols to learn, no protocol converters needed.
Key Specifications
| Parameter |
Value |
| Part Number |
1734-AENT |
| Manufacturer |
Allen-Bradley / Rockwell Automation |
| Product Type |
EtherNet/IP POINT I/O Adapter |
| Input Voltage |
24V DC nominal (10-28.8V DC) |
| Power Consumption |
4.5W max at 28.8V DC |
| Inrush Current |
6A maximum at power-up |
| POINTBus Output |
1000 mA (for connected I/O modules) |
| Network Speed |
10/100 Mbps, half or full duplex |
| Auto-Negotiation |
Yes |
| Max Modules |
63 POINT I/O modules |
| Max I/O Points |
504 |
| Topologies |
Star, Tree, Linear |
| Connector |
RJ45 (Cat 5 cable) |
| Mounting |
DIN rail, vertical |
| Protocol |
CIP / EtherNet/IP |
| Polarity Protection |
Yes |
EtherNet/IP — Why It Matters for Distributed I/O
EtherNet/IP uses standard IEEE 802.3 Ethernet hardware and TCP/IP networking, but adds the CIP application layer that gives it deterministic, industrial behaviour.
The key capability for distributed I/O is implicit messaging — the 1734-AENT and its connected controller establish a cyclic I/O connection that automatically exchanges I/O data at a defined rate without any application programming on the controller side beyond the initial configuration.
In practice, this means a CompactLogix or ControlLogix controller sees the POINT I/O modules connected to a 1734-AENT as if they were local I/O — tags appear in the controller's tag database, input data is automatically updated at the configured RPI (Requested Packet Interval), and output data is automatically written.
The controller programmer does not manage the Ethernet communication; the Logix platform handles it transparently.
The 1734-AENT also supports explicit messaging — non-cyclic messages for configuration changes, parameter reads, or diagnostics.
This is used during commissioning, troubleshooting, or when the controller needs to query module status outside the normal I/O update cycle.
IP Address Assignment and Network Commissioning
The 1734-AENT supports IP address assignment via BOOTP or DHCP — standard network tools that automatically assign an IP address to a newly connected device. Rockwell Automation provides a BOOTP/DHCP utility as part of the RSLinx and Studio 5000 toolsets.
The first time the adapter is powered on, it broadcasts a BOOTP request. The BOOTP server responds with the assigned IP address.
Once a static IP address has been assigned and confirmed, it is recommended to configure the adapter to use the fixed stored address rather than dynamic BOOTP/DHCP — this prevents IP address changes if a DHCP server is temporarily unavailable on restart.
In most production control applications, I/O adapter addresses are fixed to prevent the controller losing its I/O connection because a DHCP lease expired or a DHCP server was unreachable.
Expansion Power Supplies
The 1734-AENT provides 1000mA of POINTBus current to power connected I/O modules. For configurations that exceed this budget — which happens when many analog or specialty I/O modules are used — expansion power supplies (1734-EP24DC or equivalent) must be inserted in the rail at appropriate positions.
One expansion power supply can power up to 17 additional modules.
Planning the expansion power supply placement is an important step in designing larger POINT I/O nodes.
Frequently Asked Questions
Q1: The 1734-AENT is connected and powered but does not appear on the EtherNet/IP network. The network link LED is off. What should be checked first?
A dark link LED means the Ethernet physical connection is not established. Check the Cat 5 cable — verify it is plugged firmly into the adapter's RJ45 port, is not damaged, and connects to an active switch port.
If the cable and switch connection are confirmed good, verify the 24V DC supply voltage is within the 10-28.8V range at the adapter's power terminals.
The adapter must have power before it will attempt network communication.
If the link LED comes on but the adapter still does not appear on the network, proceed to IP address commissioning using the BOOTP utility.
Q2: How many simultaneous controller connections can the 1734-AENT support?
The 1734-AENT supports connections from multiple controllers simultaneously. In practice, one controller owns the I/O connection for output control, while additional controllers can establish listen-only connections to read input data.
This allows supervisory or monitoring systems to observe POINT I/O data without interfering with the primary controller's I/O ownership.
The total number of simultaneous connections is limited by the adapter's connection table capacity — consult the adapter's user documentation for the specific limit in the firmware version installed.
Q3: A POINT I/O module at position 32 is showing communication errors, but all other modules are working. The 1734-AENT shows normal status. What is the most likely cause?
Isolated module communication errors with a healthy adapter typically indicate a local POINTBus issue — either the affected module itself has failed, its POINTBus connections to the adjacent modules are not fully seated, or the module has drawn too much POINTBus current and triggered a power limit condition.
Remove and re-seat the module at position 32. Check whether an expansion power supply is installed if the rail has more than ~17 modules.
If the problem follows the module to a different position, the module has failed and should be replaced.
Q4: The 1734-AENT is being replaced in a running system. Does the IP address and configuration need to be re-entered?
Yes. The IP address and all configuration data are stored in the module itself, not in the I/O rack hardware.
When a new 1734-AENT is installed, it must be assigned the same IP address as the original unit — using the BOOTP utility or Studio 5000 — and the I/O chassis size configuration must match the number of modules connected.
Once the IP address is set and the controller re-establishes the I/O connection, the system should return to normal operation without changes to the controller program.
Q5: What is the difference between the 1734-AENT and the 1734-AENTR?
The 1734-AENT has one Ethernet port, supporting star and tree topologies. The 1734-AENTR has two Ethernet ports with an embedded switch, supporting Device Level Ring (DLR) topology in addition to star and linear/daisy-chain topologies.
DLR provides network-level fault tolerance — a single cable break anywhere in the ring does not disrupt I/O communication because the ring reconfigures around the break.
For applications where continuous I/O availability despite cable faults is required, the 1734-AENTR is the appropriate choice. For standard star or tree networks, the 1734-AENT is the simpler option.
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