1756-N2XT Extended Temperature Chassis – Installation & Setup Guide
Product Introduction
The Allen-Bradley 1756-N2XT belongs to the ControlLogix XT series. This specific chassis accepts standard ControlLogix modules. However, it also supports XT-rated modules for extreme conditions. You use the 1756-N2XT in ambient temperatures from -25°C to +70°C. Moreover, this model includes a conformal coated backplane. This coating resists moisture and corrosive gases. Specifically, the 1756-N2XT has 10 slots for modules. Therefore, you can build a compact yet powerful control system.
Core Value
This extended temperature chassis solves reliability problems in harsh sites. Firstly, the 1756-N2XT prevents condensation damage. Secondly, you can install it outdoors without additional climate control. In addition, this chassis maintains full backplane communication speed. It does not slow down your control logic execution. Besides, the 1756-N2XT works with standard 1756 power supplies. Furthermore, you get the same programming experience as standard ControlLogix. Consequently, you reduce enclosure costs and maintenance visits.
Technical Insights
The Allen-Bradley 1756-N2XT uses a passive backplane design. Specifically, the backplane supports 1756 ControlBus protocol. The data rate reaches 2.5 Mbit per second. Moreover, the chassis accepts both XT and standard modules. You cannot mix them in one system for XT certification though. For full XT compliance, populate all slots with XT-rated modules. The 1756-N2XT draws minimal backplane current. It needs only 0.5 A from the 1.2V supply. Additionally, the chassis includes a grounding lug. You must connect this lug to earth ground. Otherwise, electrical noise may affect analog measurements.
Installation & Maintenance
First, mount the 1756-N2XT on a flat metal panel. Use four M5 screws with lock washers. Leave 50 mm clearance above and below for airflow. Then, install the power supply in the leftmost slot. Insert modules from left to right. Push each module firmly until the locking tab clicks. Next, connect the chassis grounding wire. Use 2.5 mm² copper wire. For maintenance, inspect the backplane periodically. Look for dust or oxidation. Clean the backplane with compressed air only. Do not use solvents. Also, verify that all module locking tabs are secure. Loose tabs cause intermittent faults. Finally, check the ambient temperature regularly. The 1756-N2XT requires good ventilation.
Buyer’s Guide FAQ
Q1: Is the Allen-Bradley 1756-N2XT compatible with standard 1756 modules?
A1: Yes. You can install standard modules in the 1756-N2XT. However, the system loses XT environmental certification.
Q2: What is the slot count for the 1756-N2XT?
A2: This chassis provides exactly 10 slots. It fits standard ControlLogix modules only. It does not accept 1756 I/O modules from other families.
Q3: Can I use the 1756-N2XT in a Class 1 Division 2 area?
A3: Yes. This chassis carries hazardous location approvals. Refer to the XT product documentation for specific ratings.
Q4: How do I verify the backplane health on the 1756-N2XT?
A4: Use the controller status indicators. Also, monitor the I/O connection status in Studio 5000. Intermittent comms suggest backplane issues.
Q5: What spare parts should I stock for the 1756-N2XT?
A5: Keep one spare chassis and one backplane connector kit. Also, store spare end caps for unused slots.
