1785-L30B Allen-Bradley PLC-5 Series CPU Module | 32K Memory

Product Overview

The 1785-L30B is an industry-proven Programmable Logic Controller from the renowned PLC-5 series engineered by Allen-Bradley (Rockwell Automation). Designed for heavy-duty industrial processing, the 1785-L30B features 32K words of battery-backed user memory and comprehensive multi-network connectivity. Automation engineers rely on the 1785-L30B processor module to execute high-speed sequential logic, manage extensive universal remote I/O configurations, and ensure continuous plant-floor operation.

Technical & Environmental Specifications

• Brand: Allen-Bradley / Rockwell Automation
• Series: PLC-5 series
• Model: 1785-L30B
• Product Type: Programmable Logic Controller / Standard Processor
• User Memory Capacity: 32 Kwords (Battery-backed static RAM)
• Optional Program Backup: Compatible with 1785-ME16, -ME32, -ME64, and -M100 EEPROM modules
• Maximum I/O Capacity: 1024 points (any mix) or 1024 inputs + 1024 outputs (complementary)
• Communication Interfaces: Two (2) DH+ / Remote I/O ports (Adapter or Scanner), One (1) Serial port (RS-232, RS-423, RS-422A)
• Backplane Current Load: 2.3 Amps at 5V DC
• Power Dissipation: 12 Watts
• Operating Temperature Range: 0°C to 60°C (32°F to 140°F)
• Non-Operating Temperature Range: –40°C to 85°C (–40°F to 185°F)
• Compatible Power Supplies: 1771-P4S, 1771-P6S, 1771-P4S1, 1771-P6S1
• Backup Battery: 1770-XYC lithium cell unit

Installation & Configuration Guidelines

• Mount the 1785-L30B module directly into a compatible 1771 I/O chassis backplane slot.
• Set the front three-position key-switch to PROG mode before downloading user application logic.
• Connect programming terminals or serial devices to the 25-pin RS-232/422/423 communication port.
• Verify proper DH+ cable termination resistance on channels 1A and 1B to eliminate signal reflection over long trunk lines.

Diagnostics & System Monitoring Features

• Track processor health instantly using the dedicated front-panel LED indicators: PROC (controller state), BATT (battery health), FORCE (I/O forces active), and COMM (serial activity).
• Monitor backup battery degradation with the BATT indicator, which provides up to 5 days of reserve warning notification once low-charge thresholds are crossed.
• Utilize channel-specific status indicators to isolate communication packet errors on Data Highway Plus or Remote I/O loops.

Target Equipment & Application Scenarios

• Large discrete manufacturing and assembly lines utilizing 1771 universal remote I/O chassis.
• Continuous process control applications requiring robust multi-drop Data Highway Plus backbones.
• Legacy automation upgrade projects requiring reliable drop-in replacement controllers.
• Heavy industrial material handling and automated conveyance networks.

Ordering, Shipping, and Warranty Terms

• Inventory Status: In-stock and ready for immediate dispatch.
• Processing Window: Fast 24-48 hour order handling.
• Logistics Carriers: Secure global shipping via FedEx, UPS, and DHL.
• Warranty Coverage: Comprehensive 12-month warranty included with every 1785-L30B unit.

Global PLC Spare HUB's Insight

When maintaining vintage PLC-5 architectures, unexpected controller faults can paralyze a production line. Based on field expertise at Global PLC Spare HUB, technicians should proactively replace the 1770-XYC backup battery every 2 to 3 years, even if the BATT LED remains unlit, to prevent silent RAM data loss during unannounced plant power cuts. Additionally, verifying key-switch settings and maintaining a flashed EEPROM backup module on hand drastically reduces mean time to repair (MTTR) during emergency hardware swaps.

Frequently Asked Questions

What is the typical operational lifespan of the 1770-XYC backup battery when power is removed?

At an operating temperature of 60°C, a fully charged battery can maintain user memory for approximately 84 days at 100% initial capacity or 150 days at 50% capacity.

Can an EEPROM module be used alongside the battery-backed RAM on the 1785-L30B?

Yes, optional EEPROM modules (such as the 1785-ME32 or ME64) can be installed in the front panel slot to provide non-volatile program backup storage.

What shopping and selection criteria should engineers follow when sourcing a replacement controller?

Confirm that your total I/O point count does not exceed 1024, verify 1771 chassis power supply loading constraints (2.3A at 5V), and purchase exclusively from certified vendors offering a 12-month warranty.

What immediate troubleshooting step should be performed if the PROC indicator fails to turn green?

Verify that the key-switch is toggled to the RUN or REM position, check backplane seating to ensure proper 5V power delivery, and review error codes via the programming software.

How many universal remote I/O chassis can be linked to this processor?

The controller supports up to 28 universal remote I/O chassis within a maximum total architecture of 29 connected chassis loops.

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