Product Overview
Harsh plant environments punish standard control hardware. The Allen-Bradley 1756-L73XT is a ControlLogix-XT Logix5673 processor built for exactly those conditions. Rockwell Automation conformally coats this controller, so corrosive atmospheres and wide temperature swings do not shorten its service life. It carries 8 MB of user memory and 0.98 MB of I/O memory, enough for demanding process and discrete logic in one chassis-based unit.
Technical Specifications
| Specification | Value |
|---|---|
| User Memory | 8 MB |
| I/O Memory | 0.98 MB |
| Maximum I/O | 128,000 |
| Maximum Analog I/O | 4,000 |
| Maximum Digital I/O | 128,000 |
| Current Draw (5.1 V) | 800 mA |
| Current Draw (1.2 V) | 5 mA |
| Power Dissipation | 2.5 W |
| Thermal Dissipation | 8.5 BTU/hr |
| Isolation Voltage | 30 V continuous |
| Operating Temperature | -20…+70 °C |
| Weight | 0.25 kg |
What the Numbers Mean on the Floor
The 8 MB user memory supports 32 tasks and 100 programs per task, so complex sequencing fits without splitting logic across controllers. The 128,000 total I/O ceiling keeps room for growth. At 800 mA on 5.1 V, the draw stays modest, which simplifies power budgeting inside the chassis.
Where the 1756-L73XT Fits Best
Oil and gas operators specify this controller for wellhead panels, compressor stations, and pipeline skids where humidity and airborne contaminants attack electronics. The conformal coating and -20…+70 °C range suit outdoor cabinets in hot climates and cold starts alike. Food processing and chemical plants also benefit when washdown moisture or corrosive vapors sit near the control cabinet. Compared with a standard ControlLogix processor, the XT version trades nothing in logic capability and adds environmental protection.
Installation and Integration Notes
Mount the module in any slot of a compatible chassis. For low-temperature duty, use the 1756-A4K, 1756-A7K, 1756-A10K, 1756-A13K, or 1756-A17K chassis. For general use, the 1756-A7XT and 1756-A10XT are advisable. Standard power supplies include the 1756-PAXT, 1756-PA30XT, 1756-PBXT, and 1756-PB30XT. The USB port runs at 12 Mbps full speed and provides 30 V continuous isolation from the backplane. Note that the battery is not replaceable, so plan accordingly during commissioning.
Maintenance and Reliability
Inspect the module and chassis connections periodically, and follow the manufacturer’s safety manual for all service work. Keep cabinet filters clean to protect the conformal coating’s advantage. The unit tolerates 10–500 Hz vibration, 30 g operating shock, and 50 g non-operating shock, so it holds up in vibrating skids. Non-operating temperature spans -40…+85 °C, and humidity from 5 to 95% is acceptable. These ratings translate into fewer unplanned stoppages and lower total cost of ownership.
Selection Checklist
Before ordering, confirm your chassis model, power supply, and I/O count against the 128,000-point ceiling. Verify current lifecycle status and availability with Oil AutoTech before ordering. Contact Oil AutoTech today for pricing and availability.
Frequently Asked Questions
What makes the 1756-L73XT different from a standard ControlLogix processor?
It is conformally coated and rated for -20…+70 °C operation, so it survives harsh and corrosive environments that damage standard modules.
How much user memory does this controller provide?
It offers 8 MB of user memory and 0.98 MB of I/O memory, supporting 32 tasks and 100 programs per task.
Which chassis should I use for low-temperature applications?
Use the 1756-A4K, 1756-A7K, 1756-A10K, 1756-A13K, or 1756-A17K chassis.
Is the battery replaceable?
No, the battery is not replaceable. Plan for this during commissioning and lifecycle planning.
Can the 1756-L73XT handle high-vibration installations?
Yes. It is rated for 10–500 Hz operating vibration and 30 g operating shock.
