PLC-5-26

The Allen-Bradley PLC-5-26 is an enhanced PLC-5 Processor with protected memory. It is equivalent to the PLC-5-20 processor but with an added memory protection feature. The protected memory allows limited access to proprietary or critical areas of programs. It can restrict the use of processor operations or protect the processor memory and I/O words. The PLC-5-26 processor has maximum user memory of 16K words. It has up to 512 total I/O (any number of the I/O can be inputs or outputs) with 512 complementary inputs and outputs. It has 4 (0 – 3) I/O racks for I/O addressing. It has an I/O scan time per rack of 10ms at 57.6 kb/s, 7ms at 115.2 kb/s, and 3ms at 230.4 kb/s. The PLC-5-26 requires a backplane current of 2.3A at 5V and has a maximum power dissipation of 12W. It has EEPROM-based protected memory modules and battery-backed RAM for data backup. It is installed in the left-most slot of the 1771 I/O chassis and requires one slot. The PLC-5-26 has a maximum of 13 I/O chassis with 12 universal remote I/O chassis. For communication, it has a 1 DH+ port (fixed), 1 DH+ or Remote I/O (Adapter or Scanner) port, and 1 serial port configurable for RS-232, RS-423, and RS-422A communications. The PLC-5-26 processor has LED status indicators and a timed interrupt routine for examining specific information status. It has a user-programmable fault response for system diagnostics before it crashes.