Allen-Bradley 1790D-TN4C0 Terminal Base Unit – Installation & Maintenance for D-Series
Product Introduction
The Allen-Bradley 1790D-TN4C0 provides the physical wiring interface for your D-Series I/O modules. This base unit works specifically with 24V DC power. It holds removable terminal blocks. You connect field devices like sensors and actuators here. Rockwell Automation designed this model for simplicity. Firstly, it reduces wiring errors. Moreover, the compact form factor fits tight enclosures. You can mount it on a DIN rail. Therefore, installation becomes faster. Specifically, this unit has no built-in I/O points. Instead, it supports plug-in modules. Each 1790D-TN4C0 serves one I/O module.
Core Value
This terminal base delivers reliable field wiring termination. Its key benefit is easy maintenance. You can remove the RTB without disconnecting field wires. Besides that, the 1790D-TN4C0 improves system uptime. Troubleshooting becomes simpler. You swap a faulty module quickly. Meanwhile, the base ensures secure connections. Vibration won't loosen wires easily. Furthermore, this model supports standard 24V DC controls. It matches most industrial sensors. Consequently, you reduce spare parts inventory. The Allen-Bradley 1790D-TN4C0 also lowers installation labor costs. Its clarity labeling speeds up panel building.
Technical Insights
The Allen-Bradley 1790D-TN4C0 operates at 24V DC nominal voltage. It accepts a range from 20.4V to 28.8V DC. This tolerance handles power fluctuations. The base unit provides a backplane interface. It communicates with the controller through the D-Series bus. Additionally, the 1790D-TN4C0 has a current rating of 4A maximum. Use proper overcurrent protection. The operating temperature ranges from 0°C to 55°C. Store it between -40°C to 85°C. Also, the unit meets NEMA standards for open equipment. Enclosure rating is IP20. Therefore, install it inside a control cabinet. The terminal base uses 4 mounting screws or a DIN rail clip.
Installation & Maintenance
Install the Allen-Bradley 1790D-TN4C0 on a grounded DIN rail. Firstly, snap the base onto the rail. Secondly, secure it with the locking screws. Thirdly, insert the I/O module onto the base. Then, connect field wiring to the RTBs. Use shielded cable for analog signals. Torque screws to 0.5 Nm. Moreover, follow these maintenance tips:
Power down before removing modules.
Check for loose wires every 6 months.
Clean dust with compressed air.
Verify 24V DC polarity matches labeling.
For replacement, pull the RTB upward first. Then, remove the I/O module. Lastly, unclip the 1790D-TN4C0 from the DIN rail.
Buyer’s Guide FAQ
1. What is the Allen-Bradley 1790D-TN4C0 used for?
This unit serves as a terminal base for D-Series Compact I/O modules. It connects field devices to the backplane.
2. Does the 1790D-TN4C0 include any I/O points?
No, it only provides wiring terminals. You need a separate I/O module to install on top of this base.
3. What power supply works with the 1790D-TN4C0?
Use a 24V DC power supply. The acceptable range is 20.4V to 28.8V DC.
4. How do I mount the Allen-Bradley 1790D-TN4C0?
Mount it on a standard 35mm DIN rail. Alternatively, use M5 screws for panel mounting.
5. Can I replace a module without rewiring the 1790D-TN4C0?
Yes. The removable terminal block stays in place. Simply pull off the old module and snap on the new one.
