1783-US8T: Installation, Wiring, and Network Design Guide
The 1783-US8T is an 8-port 10/100 Fast Ethernet unmanaged industrial switch in the Allen-Bradley Stratix 2000 family. It provides reliable Layer 2 switching for EtherNet/IP control networks in industrial environments. As an unmanaged switch, it requires no software configuration — connect power, plug in Ethernet cables, and it operates immediately with auto-negotiation and auto-MDIX on all ports. The Stratix 2000 is DIN-rail mountable, rated for -10 to +60°C, and supports dual redundant 24VDC power inputs. This guide covers DIN rail installation, power wiring, grounding, Ethernet cabling, LED diagnostics, and network topology best practices.
Contents
1. Switch Overview
The 1783-US8T is a fixed 8-port unmanaged Ethernet switch designed for industrial automation networks. It provides store-and-forward Layer 2 switching with auto-negotiation (10/100 Mbps) and auto-MDIX on all ports. The switch requires no configuration — it learns MAC addresses automatically and forwards traffic based on its MAC address table.
Catalog Number Breakdown
| Code | Meaning | Value |
|---|---|---|
| 1783 | Platform | Stratix — industrial Ethernet infrastructure |
| US | Switch type | Unmanaged Switch |
| 8T | Port configuration | 8 copper (RJ45) ports, 10/100 Fast Ethernet |
| /B | Series | Series B (current production) |
Key Specifications
| Parameter | Value |
|---|---|
| Ethernet Ports | 8 x 10/100 BASE-T Fast Ethernet (RJ45) |
| SFP Ports | None |
| Switching Method | Store-and-forward |
| Auto-Negotiation | Yes — 10/100 Mbps per port |
| Auto-MDIX | Yes — straight-through or crossover cables |
| MAC Address Table | 2K entries |
| Power Input | 24V (12...48V DC, 18...30V AC, 50/60 Hz), SELV |
| Redundant Power | Yes — dual power inputs (PWR1, PWR2) via 4-pin connector |
| Power Consumption, max | 3.4 W |
| Inrush Current, max | 1.31 A |
| Current, nominal | DC 180 mA / AC 360 mA |
| Current, max | DC 380 mA / AC 750 mA |
| Operating Temperature | -10 to +60°C (14 to +140°F) |
| Temperature, ambient, max | 60°C (140°F) |
| Enclosure Type Rating | IP30 (open-style) |
| Mounting | DIN rail |
| North American Temp Code | T4 |
| ATEX / IECEx Temp Code | T4 |
Unmanaged vs. Managed — When to Use Each
The Stratix 2000 is an unmanaged switch — it has no web interface, no CLI, no VLAN support, and no configuration options. It is ideal for simple network segments where you need additional Ethernet ports without management complexity. For applications requiring VLANs, QoS, port security, DLR ring topology, or diagnostics via Studio 5000, use a managed switch such as the Stratix 5200 (1783-CMS) or Stratix 5800 (1783-MMS).
2. Hardware Installation
The 1783-US8T mounts vertically on a standard 35mm DIN rail. The switch is supplied as open-type equipment and must be mounted within an enclosure suitable for the environmental conditions.
Enclosure Requirements
Minimum clearances to prevent overheating:
| Clearance | Minimum Distance |
|---|---|
| Top and bottom | 51 mm (2.0 in.) |
| Sides | 51 mm (2.0 in.) |
| Front | 64 mm (2.50 in.) |
Additional requirements:
- Front-panel status indicators must be easily readable.
- Access to ports must be sufficient for unrestricted cabling.
- Power connector must be within reach of the power source.
DIN Rail Mounting Steps
- Position the switch above the DIN rail. Place the switch so that the top of the DIN rail mounting clip is slightly above the upper DIN rail edge.
- Angle and slide downward. With the bottom of the switch angled away from the panel, slide the switch downward until the mounting clip spring is behind the top edge of the DIN rail.
- Press the switch downward to compress the spring.
- Press the bottom toward the panel until the clip locks into place over the bottom edge of the DIN rail.
DIN Rail Removal
- Gently push the switch downward to compress the mounting clip spring.
- Rotate the bottom of the switch away from the DIN rail until the bottom of the mounting clip is clear of the lower rail.
- Lift the switch up until the mounting clip and springs clear the upper DIN rail.
DIN Rail Material
Use zinc-plated yellow-chromate steel DIN rail to assure proper grounding. The use of other DIN rail materials (for example, aluminum or plastic) that can corrode, oxidize, or are poor conductors, can result in improper or intermittent grounding. Secure DIN rail to mounting surface approximately every 200 mm (7.8 in.) and use end-anchors appropriately.
3. Power Wiring
The 1783-US8T has a 4-pin power terminal connector on top of the switch that supports dual redundant power inputs (PWR1 and PWR2). Both inputs accept 24V DC (range 12...48V DC) or 18...30V AC.
Power Connector Pinout
| Pin | DC Wiring | AC Wiring |
|---|---|---|
| Pin 1 | PWR1: - (negative) | PWR1: N (neutral) |
| Pin 2 | PWR1: + (positive) | PWR1: L (line) |
| Pin 3 | PWR2: - (negative) | PWR2: N (neutral) |
| Pin 4 | PWR2: + (positive) | PWR2: L (line) |
Power Connection Steps
- Disconnect the power terminal connector from the top of the switch.
- Insert the power wires into the power terminal connector. The stripped conductor length of the power cable is 3...5 mm. For proper polarity, use the cable pinout diagram on the switch label.
- Tighten the power connector by using a screwdriver. Torque: 0.50...0.56 N·m (4.5...5.0 in·lb).
- Plug the power terminal connector back into the device.
Hazardous Location Power Wiring
If you connect or disconnect the removable terminal block (RTB) with field side power applied, an electric arc can occur. This could cause an explosion in hazardous location installations. Be sure that power is removed or the area is nonhazardous before proceeding.
Redundant Power
The Stratix 2000 supports dual power inputs (PWR1 and PWR2). Connect two independent 24VDC power supplies for redundancy — if one supply fails, the switch continues operating on the other. The PWR1 and PWR2 status LEDs indicate which power inputs are active. For single-supply installations, use either PWR1 or PWR2.
Grounding
The switch must be grounded to chassis/earth ground via the ground screw on top of the switch.
| Parameter | Value |
|---|---|
| Grounding resistance | Less than 5 Ω |
| Ground wire | Minimum 2.5 mm² (14 AWG) copper wire with suitable ring terminal |
| Ground screw torque | 0.91 N·m (8.05 in·lb) |
Grounding Steps
- Remove the ground screw from the top of the switch using a Phillips screwdriver.
- Strip the ground wire per manufacturer's guidelines.
- Crimp a ring terminal lug onto the ground wire.
- Slide the ground screw through the ring terminal.
- Tighten the ground screw and ring terminal to the top of the switch using a ratcheting torque screwdriver. Torque: 0.91 N·m (8.05 in·lb).
- Attach the other end of the ground wire to a grounded bare metal surface, such as a grounded DIN rail.
4. Ethernet Connections
The 1783-US8T has 8 RJ45 Ethernet ports supporting 10/100 Mbps Fast Ethernet. All ports support auto-negotiation and auto-MDIX, so you can use either straight-through or crossover cables.
Cabling Requirements
| Parameter | Value |
|---|---|
| Cable Type | Twisted four-pair, Category 5e or better, with RJ45 connectors |
| Cable Style | Straight-through or crossover (auto-MDIX auto-detects) |
| Max Segment Length | 100 m (328 ft) per IEEE 802.3 specification |
| Shielded Cable | Recommended for industrial environments to reduce EMI |
10/100 Copper Port Pin Assignments
| Pin | MDIX Signal | MDI Signal |
|---|---|---|
| 1 | RD+ | TD+ |
| 2 | RD- | TD- |
| 3 | TD+ | RD+ |
| 6 | TD- | RD- |
| 4, 5, 7, 8 | Not used | Not used |
Auto-MDIX Simplifies Cabling
With auto-MDIX, the switch automatically detects the cable type (straight-through or crossover) and configures the interface accordingly. You can connect any device — PLC, HMI, drive, another switch, or a PC — using the same standard Ethernet patch cable. No crossover cables are required.
Use Shielded Cables in Industrial Environments
While the switch supports standard unshielded Cat5e cables, industrial environments with VFDs, motor starters, and high-current switching can generate significant electromagnetic interference. Use shielded Ethernet cables (STP/FTP) and ensure shields are properly grounded at one end to maintain reliable communication.
5. LED Indicators & Diagnostics
The 1783-US8T has status LEDs on the front panel for power supply status and per-port link/activity status.
Power LEDs
| LED | Color | State | Meaning |
|---|---|---|---|
| PWR1 | Green steady | Power input 1 active | PWR1 is receiving valid power |
| PWR1 | Off | No power on input 1 | PWR1 supply not connected or failed |
| PWR2 | Green steady | Power input 2 active | PWR2 is receiving valid power |
| PWR2 | Off | No power on input 2 | PWR2 supply not connected or failed |
Port Status LEDs
| LED | Color | State | Meaning |
|---|---|---|---|
| Port (1-8) | Off | No link | No device connected or link not established |
| Port (1-8) | Green steady | Link established | Valid Ethernet link at 10 or 100 Mbps |
| Port (1-8) | Green flashing | Activity | Data is being transmitted or received on the port |
| Port (1-8) | Flashing at power-on | Self-test | Normal — port LEDs flash briefly during switch initialization |
Common Issues and Resolutions
| Symptom | Likely Cause | Resolution |
|---|---|---|
| No port LEDs light up | No power to switch | Verify 24VDC is connected to the power terminal connector. Check PWR1/PWR2 LEDs. Verify power supply output voltage is within 12...48V DC range. |
| PWR1 or PWR2 LED off | Power supply not connected or failed | Check wiring polarity at the 4-pin power connector. Verify the power supply is energized and within the 12...48V DC (or 18...30V AC) range. |
| Port LED off with cable connected | No link | Verify the cable is seated in both the switch and the connected device. Try a known-good cable. Confirm the connected device is powered on and its Ethernet port is functioning. |
| Port LED green steady but no communication | Network configuration issue | The switch itself is functioning (link is up). Check IP addressing, subnet masks, and gateway settings on the connected devices. For EtherNet/IP, verify CIP connection parameters in Studio 5000. |
| Intermittent communication or CRC errors | EMI or cable quality issue | Replace with shielded Cat5e or Cat6 cable. Route Ethernet cables away from VFDs, motor power cables, and high-voltage switching equipment. Ensure cable runs do not exceed 100 m. |
| Switch not forwarding traffic between ports | MAC table or loop issue | Power-cycle the switch to clear the MAC address table. Check for network loops — unmanaged switches do not support Spanning Tree Protocol (STP). A loop will cause a broadcast storm and network failure. |
Network Loops
The Stratix 2000 is an unmanaged switch with no Spanning Tree Protocol (STP) support. If you accidentally create a loop (connecting two ports on the same switch to the same network segment, or connecting two switches with redundant paths), a broadcast storm will occur, flooding the network and causing all devices to lose communication. Always verify your cabling topology before powering on. For ring topologies requiring redundancy, use a managed switch with DLR or REP support.
6. Network Design Best Practices
The Stratix 2000 is commonly deployed as an access-layer switch in EtherNet/IP industrial networks. Here are best practices for integrating it into your control system.
Topology: Star Configuration
The 1783-US8T is best used in a star topology where multiple field devices connect to a central switch. Typical connections include CompactLogix/ControlLogix controllers, PanelView HMIs, PowerFlex drives, POINT I/O adapters, and other EtherNet/IP devices.
One Switch per Panel
Place a Stratix 2000 in each remote panel or machine station. Uplink to a backbone managed switch (Stratix 5200 or 5800) via one port. Use the remaining 7 ports for local devices. This keeps cable runs short and simplifies troubleshooting.
Port Allocation Planning
| Port | Recommended Assignment |
|---|---|
| Port 1 | Uplink to backbone switch or controller |
| Port 2 | CompactLogix or POINT I/O adapter |
| Port 3 | PanelView HMI |
| Port 4 | PowerFlex drive |
| Port 5-8 | Additional field devices or reserved for expansion |
Label Your Ports
Document which device is connected to each port. Attach a label to the switch or enclosure door with the port map. This saves significant troubleshooting time during commissioning and maintenance.
Avoid Common Mistakes
No VLANs on Unmanaged Switches
The Stratix 2000 does not support VLANs. All ports are in the same broadcast domain. If you need to segment traffic between control and information networks, use a managed switch.
No Ring Topology
Do not connect the Stratix 2000 in a ring (DLR or REP). It has no ring protocol support and will create a broadcast storm. Use a star topology only.
7. Related Stratix 2000 Switches
The Stratix 2000 family includes switches with different port counts and fiber options:
| Catalog Number | Ports | Port Types | Key Feature | Typical Application |
|---|---|---|---|---|
| 1783-US5T/B | 5 | 5 FE RJ45 | Compact 5-port | Small panels, machine stations |
| 1783-US5TG/B | 5 | 5 GE RJ45 | Gigabit version | High-bandwidth applications |
| 1783-US8T/B | 8 | 8 FE RJ45 | Standard 8-port — this guide | General purpose industrial Ethernet |
| 1783-US6T2F/B | 8 | 6 FE + 2 MM fiber | Multimode fiber uplinks | Long-distance or EMI-heavy uplinks |
| 1783-US6T2H/B | 8 | 6 FE + 2 SM fiber | Singlemode fiber uplinks | Very long distance uplinks |
| 1783-US8TG2GX/B | 10 | 8 GE + 2 GE SFP | Gigabit with SFP slots | High-performance backbone |
| 1783-US16T/B | 16 | 16 FE RJ45 | High-density 16-port | Large panels with many devices |
| 1783-US16T2S/B | 18 | 16 FE + 2 SFP | 16-port with fiber uplinks | Large panels needing fiber backbone |
8. Related Guides
| Guide | Description |
|---|---|
| CompactLogix 5069-L306ER Setup Guide | First-time setup for the CompactLogix 5380 controller — often the primary device on a Stratix 2000 network segment. |
| 1734-IB8 POINT I/O Digital Input Guide | The 1734-AENT POINT I/O adapter connects to the Stratix 2000 via EtherNet/IP. |
Reference Documentation
The following Rockwell Automation publications were used as references for this guide. These are the official manufacturer documents for the hardware covered in this article.
| Publication | Description | Download |
|---|---|---|
| 1783-TD002 | Stratix Ethernet Device Specifications Technical Data | |
| 1783-IN003 | Stratix 2000 Ethernet Unmanaged Switches Installation Instructions |
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