Allen-Bradley 1785-L30B PLC-5/30 Programmable Controller
The Allen-Bradley 1785-L30B, also cataloged as the 1785-L30B PLC-5 Processor, operates as a dedicated hardware component for centralized logic control and signal execution within Allen-Bradley PLC-5 systems. It mounts directly into a PLC-5 chassis to execute sequential control, ladder logic processing, and multi-channel I/O manipulation across plant-wide industrial automation networks.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1785-L30B |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 2.73 lbs (1.24 kg) |
| Dimensions | Standard PLC-5 Processor Single-Slot Chassis Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | 2.3 A at 5 VDC (backplane load) |
| Memory Capacity | 32 K Word SRAM |
| Max Analog I/O | 1024 Analog I/O points |
| Communication Ports | 2 DH+ / Remote I/O channels, 1 RS-232-C channel |
| System Architecture | Allen-Bradley PLC-5 Platform |
Backplane Bus Communication Velocity & Network Determinism
The 1785-L30B processor manages high-speed backplane bus communication velocity across local and extended 1771 I/O racks. Built-in Data Highway Plus (DH+) and Remote I/O (RIO) ports enable deterministic networking and peer-to-peer data transfers between legacy control architectures and supervisory human-machine interfaces (HMI). Internal firmware routines allocate execution priorities to maintain scan-time repeatability while processing 32 K Word SRAM program logic and handling dense 1024 analog I/O channel updates.
Frequently Asked Questions
Q: What power supply allocation is required for the 1785-L30B processor backplane load?
A: The processor draws 2.3 A at 5 VDC directly from the 1771 chassis backplane power supply, which must be factored into total rack power budget calculations.
Q: How are communication protocols configured on the two dual-purpose ports of the 1785-L30B?
A: The two DH+/RIO channels can be individually configured via onboard DIP switches or system software to operate as Data Highway Plus nodes or Remote I/O scanner/adapter ports.
Field Installation Guidelines
- Chassis Slot Insertion: Turn off rack power prior to installation. Insert the 1785-L30B processor into the leftmost slot (Slot 0) of the 1771 I/O chassis and engage the retaining latches fully.
- Communication Cabling: Connect Belden 9463 twinaxial cable to the 3-pin DH+/RIO connectors. Ensure proper 150-ohm or 82-ohm termination resistors are installed at both physical ends of the network trunk.
- Serial Configuration: Use a shielded 9-pin RS-232 cable for direct programming or serial device connection, maintaining cable lengths under 15 meters (50 feet) to prevent signal noise.
Allen-Bradley 1785-L30B PLC-5/30 Programmable Controller
Allen-Bradley 1785-L30B PLC-5/30 Programmable Controller
The Allen-Bradley 1785-L30B, also cataloged as the 1785-L30B PLC-5 Processor, operates as a dedicated hardware component for centralized logic control and signal execution within Allen-Bradley PLC-5 systems. It mounts directly into a PLC-5 chassis to execute sequential control, ladder logic processing, and multi-channel I/O manipulation across plant-wide industrial automation networks.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1785-L30B |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 2.73 lbs (1.24 kg) |
| Dimensions | Standard PLC-5 Processor Single-Slot Chassis Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | 2.3 A at 5 VDC (backplane load) |
| Memory Capacity | 32 K Word SRAM |
| Max Analog I/O | 1024 Analog I/O points |
| Communication Ports | 2 DH+ / Remote I/O channels, 1 RS-232-C channel |
| System Architecture | Allen-Bradley PLC-5 Platform |
Backplane Bus Communication Velocity & Network Determinism
The 1785-L30B processor manages high-speed backplane bus communication velocity across local and extended 1771 I/O racks. Built-in Data Highway Plus (DH+) and Remote I/O (RIO) ports enable deterministic networking and peer-to-peer data transfers between legacy control architectures and supervisory human-machine interfaces (HMI). Internal firmware routines allocate execution priorities to maintain scan-time repeatability while processing 32 K Word SRAM program logic and handling dense 1024 analog I/O channel updates.
Frequently Asked Questions
Q: What power supply allocation is required for the 1785-L30B processor backplane load?
A: The processor draws 2.3 A at 5 VDC directly from the 1771 chassis backplane power supply, which must be factored into total rack power budget calculations.
Q: How are communication protocols configured on the two dual-purpose ports of the 1785-L30B?
A: The two DH+/RIO channels can be individually configured via onboard DIP switches or system software to operate as Data Highway Plus nodes or Remote I/O scanner/adapter ports.
Field Installation Guidelines
- Chassis Slot Insertion: Turn off rack power prior to installation. Insert the 1785-L30B processor into the leftmost slot (Slot 0) of the 1771 I/O chassis and engage the retaining latches fully.
- Communication Cabling: Connect Belden 9463 twinaxial cable to the 3-pin DH+/RIO connectors. Ensure proper 150-ohm or 82-ohm termination resistors are installed at both physical ends of the network trunk.
- Serial Configuration: Use a shielded 9-pin RS-232 cable for direct programming or serial device connection, maintaining cable lengths under 15 meters (50 feet) to prevent signal noise.
