Purchase now: Allen Bradley 1747-L30B Fixed Controller
Purchase now: Atlantechdrives provides you the 1747-L30B, a high-capacity «Fixed Hardware Style» programmable controller engineered by Allen Bradley for the dependable SLC 500 platform. When the standard 20 I/O footprint is insufficient for your machine’s requirements, the 1747-L30B steps in to provide a 50% increase in capacity without requiring a leap to a fully modular, multi-card chassis system. This unit provides 30 total I/O points: 18 inputs operating on 120V AC, and 12 solid-state AC Triac outputs. It is highly sought after for upgrading standalone manufacturing equipment, commercial HVAC management systems, and mid-sized pumping stations that require numerous 120V AC interlocks and high-cycle AC output actuation.
Technical Specifications of the 1747-L30B
Powered by a standard 120/240V AC line, the 1747-L30B is an all-in-one automation workhorse. It features 1K of embedded instruction memory and utilizes the robust DH-485 network for programming access and factory floor integration.
- Part Number: 1747-L30B
- Controller Type: Fixed Hardware Style (Expanded Footprint)
- Total I/O Points: 30 Points
- Inputs: Eighteen (18) 120V AC
- Outputs: Twelve (12) AC Triac Solid-State
- Line Power Requirement: 120 / 240V AC (50/60 Hz)
- Memory Capacity: 1K Instructions
- Programming Interface: DH-485 via RJ45 port
- Expansion: Ribbon cable support for 2-slot external chassis
Expert Tips: Heat Dissipation and Triac Load Limits
Upgrading to 12 solid-state AC outputs requires careful thermal planning inside your control panel. Expert Tip: While solid-state Triacs do not suffer from mechanical wear like relays do, they generate significantly more internal heat. Each of the 12 outputs on the 1747-L30B can handle a specific maximum continuous current, but the total combined current for all 12 outputs simultaneously is strictly limited to prevent the internal circuit board from melting. If your application requires turning on twelve 120V AC solenoids at the exact same time, you must calculate the total amperage. If it exceeds the module’s thermal rating, you should use interposing relays to handle the heavy current loads, utilizing the PLC’s Triacs only to trigger the relay coils.
Maintenance and System Expansion
One of the strongest features of the 1747-L30B is its ability to grow. If 30 I/O points eventually become a bottleneck, you do not have to discard the controller. By removing the side cover, you can attach an interconnect ribbon cable to an external 2-slot SLC chassis. This allows you to slide in any standard 1746 specialty module—such as an analog input card (1746-NI4) or a thermocouple module (1746-NT4)—seamlessly integrating modular flexibility into a fixed hardware footprint.
Frequently Asked Questions (FAQs)
Q: What is the difference between the 1747-L30A and the 1747-L30B?
A: The input voltage (120V AC) and total point count (30) are identical. The difference lies entirely in the output hardware. The 1747-L30A uses mechanical relays, while the 1747-L30B uses solid-state AC Triacs for faster switching and longer electrical life.
Q: Does this controller provide 24V DC power for sensors?
A: Yes. Like most AC-powered fixed SLC 500 units, the 1747-L30B provides a small «User Power» terminal that outputs 24V DC at approximately 200 mA, which is highly useful for powering a few photoelectric eyes without needing an external supply.
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This 30-point fixed SLC controller offers a robust all-in-one solution for systems requiring 120/240V AC power.
