A recent programmable logic controller comes with on-board I/O plus a full-function operator panel with numeric keypad to simplify tough jobs. The Jazz PLC from Unitronics, Quincy, Mass., (unitronics.com) also includes 24k of ladder-programming software, math features, along with functions for store/load, compare, clock, and vector operations. Jazz supports interrupt, loops, and immediate read/write to I/Os. Up to 60 user-designed HMI screens can display instructions, conditional messages, or variable data such as time, date, bit status, timer, and integer values.

Communication is through SMS messaging for real-time remote control by any GSM cell phone or with remote access utilities. These allow downloading and debugging Jazz programs, operating the controller's panel, and viewing run-time parameters by remote PCs. Communications can also be completed with Modbus and OPC/DDE servers.