Product Summary
The Allen-Bradley 1785-L26B provides a robust standard processor for your automation needs. This PLC-5 controller manages up to 512 I/O points with 16K memory. It offers protected memory and battery-backed SRAM for reliable data retention. This processor integrates easily with 1771 I/O chassis.
Expert Technical Evaluation & Performance Review
Robust Processing and Memory Architecture
The 1785-L26B delivers a powerful 16-kiloword memory capacity for complex logic. This processor uses battery-backed static RAM to preserve your program. You can also use EEPROM for a reliable program backup. The protected memory feature prevents unauthorized access to critical code. This controller handles demanding applications with consistent performance.
Comprehensive I/O and Scanning Capabilities
This PLC-5 processor supports a maximum total of 512 I/O points. You can configure these inputs and outputs in any mix. The 1785-L26B also allows 512 inputs plus 512 outputs in a complementary setup. It handles up to 512 analog I/O channels for precise process control. The I/O scan time varies by network speed. It scans a rack in 10 ms at 57.6 kbits/s. The scan time drops to 3 ms at 230.4 kbits/s. This controller supports up to 13 I/O chassis for large systems.
Flexible Hardware Addressing Modes
The 1785-L26B supports three distinct hardware addressing modes. The half-slot mode works with any mix of 8, 16, and 32-point modules. The 1-slot mode handles 8 or 16-point modules with a pair of 32-point modules. The 2-slot mode works with 8-point modules or a pair of 16-point modules. This flexibility allows you to optimize your I/O layout.
Communication and Network Connectivity
This controller offers multiple ports for versatile communication. It includes a 25-pin D-shell serial port for RS-232 and RS-423 interfaces. The 1785-L26B also has a Data Highway Plus port for network connection. A Remote I/O port provides a channel for remote device control. The control coprocessor expansion port adds further functionality.
Environmental Durability and Certification
The 1785-L26B operates reliably in harsh industrial environments. It works within an ambient temperature range of 0 to 60 degrees Celsius. The controller functions at humidity levels between 5 and 95 percent. It withstands an operational shock of 30G for rugged use. The unit resists vibration of 1G at 10 to 500 Hertz. It holds UL, CE, CSA, and C-TICK certifications for global compliance.
Product Procurement & Buyer Guide
Key Specifications for Selection
Engineers must consider the 1785-L26B backplane current draw. This processor draws a maximum of 2.6 amps at 5 Volts DC. You must ensure your 1771 I/O chassis power supply meets this demand. The unit provides voltage isolation between communication ports. This isolation tests at 500 Volts for one minute. The isolation between the port and relay cartridge tests at 1000 Volts.
Compatibility with I/O Modules
This controller works with a wide range of Allen-Bradley modules. It supports most 1771 I/O modules for standard applications. The 1785-L26B also works with 1794 I/O, 1746 I/O, and 1791 modules. It handles 8-point, 16-point, 32-point, and intelligent I/O modules. This broad compatibility simplifies system design and upgrades.
Installation and Mounting Details
The 1785-L26B installs in the left-most slot of the 1771 I/O chassis. The unit weighs approximately 1.42 kilograms or 3 pounds. It comes in an open-style enclosure for easy integration. The controller supports the 1785-RC relay cartridge for external device interfacing. You can connect up to four I/O racks using this processor.
Logistics & Standard Packaging Details
- One Allen-Bradley 1785-L26B PLC-5/26 Processor
- One factory-installed battery for SRAM backup
- Standard anti-static packaging for safe transport
- Product documentation and compliance labels
- Express delivery shipping is available via FedEx, UPS, and DHL
