The PLC-5® processors are single-slot modules that are placed into the left-most slot of a 1771 I/O chassis. They are available in a range of I/O, memory, and communication capability.
PLC-5 processors have ports configurable for either a Data Highway Plus messaging communication link or a Universal Remote I/O link. As a Universal Remote I/O port, it can be configured as either an I/O scanner port or an I/O adapter port. As an I/O scanner port, it monitors and controls the I/O on the link by communicating with the I/O adapters for those I/O. As an adapter port, it communicates only with the I/O scanner port on the link, passing a maximum of one I/O rack of input and output data between the two to provide distributed processing.
All PLC-5 processors have Data Highway Plus and RS-232-C/422-A/423-A communication ports. In addition to these ports, each Ethernet PLC-5 processor has an Ethernet communication port, and each ControlNet PLC-5 processor has a ControlNet communication port.
Although each Ethernet PLC-5 processor has on-board Ethernet ports; additional Ethernet ports can be added to any PLC-5 processor system with a 1785-ENET Ethernet Interface Module. PLC-5 processors do not have an on-board DeviceNet port. A DeviceNet port can be added to the system with a 1771-SDN scanner module.
- Ladder-logic and structured-text programming
- Advanced instruction set including file handling, sequencer, diagnostic, shift register, immediate I/O, and program control instructions
- Multiple main control programs for segregation of control tasks
- Processor input interrupts and global status flags
- Programmable fault response for reacting to a fault before the system goes down
- Timed interrupt routine for examining specific information at specific time intervals
- Protected memory selectable by word on selected processors
- 512 through 3072 maximum forcible I/O in any mix
- Up to 50,176 maximum non-forcible I/O
- Processor-resident local I/O (1771 I/O modules)
- Extended-local I/O on selected processors (1771 I/O modules)
- Universal Remote I/O (1746, 1771, and 1794 I/O modules and 1791 I/O blocks)
- DeviceNet I/O (1794 I/O modules, 1792D I/O blocks)
- ControlNet I/O on selected processors (1771, 1734, 1794, 1797 I/O modules)
- Universal Remote I/O ports can be configured as either an I/O scanner port or an I/O adapter port
Built-in Web Services
Ethernet PLC-5 processors (1785-L20E, -L40E, and -L80E), and the Ethernet interface module (1785-ENET) provide built-in web capabilities:
- Web Diagnostics and Module Information lets a standard web browser access information stored in the PLC-5 processor data table, including module diagnostic information (requires RSLogix5, version 5.2 or later).
- Web User Provided Pages allows for unique Web page creation to provide custom data table information. Any Internet user who has network access to the PLC-5 processor can view these pages, which can be either HTML pages that contain data table elements, text and images, or Custom Data Monitor pages that contain data table elements in table form.
- Domain Name Service (DNS) lets Internet users access the built-in Web server by a specified name instead of by IP address (requires RSLogix5, version 5.2 or later).
PLC-5 Processors with Protected Memory (1785-L26B, -L46B, L86B, -L46C15)
All enhanced PLC-5 processors have memory protection. However, those processors designated as having the memory protection feature have the added capability of limiting access to individual words.
Choose a PLC-5 processor with protected memory when access must be limited to critical or proprietary areas of programs, selectively guard processor memory and I/O words, or restrict use of processor operations.
The PLC-5 protected memory feature expands system validity and security beyond what is provided by the password-and-privilege capability of the other PLC-5 enhanced processors. Custom software protection schemes can be designed for each application.
Rockwell Software programming software can be used to assign class privileges to specific user accounts or a user job function, such as system administrator, plant engineer, maintenance engineer, or operator. Using four privilege classes and associated passwords, access can be limited to critical program areas and restrict access to:
- Communication channels
- Remote nodes attached to a DH+ or ControlNet network
- Program files
- Data files
- Individual data words
The PLC-5/26, PLC-5/46, and PLC-5/86 protected processors are equivalent to the PLC-5/20, PLC-5/40, and PLC-5/80 standard processors, respectively, plus the added memory protection feature. These processors are listed under the heading “Standard PLC-5 Processors with Protected Memories” in the PLC-5 Processor selection tables.
The PLC-5/46C15 protected processor is equivalent to the PLC-5/40C15 ControlNet processor plus the added memory protection feature. This processor is listed under the heading “ControlNet PLC-5 Processors with Protected Memories” in the PLC-5 Processor selection tables.