Low-cost PLC/HMI with direct temperature inputs

If your system or process requires temperature measurement, you are familiar with the dilemma—should you use a PID controller, or a high-level PLC that includes PID functionality? The PID controller is cheaper, but you must set it up as an extra unit, program it, and establish communication with other parts of the system.
By Control Engineering Staff December 30, 2008

If your system or process requires temperature measurement, you are familiar with the dilemma—should you use a PID controller, or a high-level PLC that includes PID functionality? The PID controller is cheaper, but you must set it up as an extra unit, program it, and establish communication with other parts of the system. Using a PLC can save a lot of work, but also can be more expensive. Two new Jazz PLCs from Unitronics can solve the dilemma.

With its embedded HMI and direct temperature measurement inputs, a Jazz PLC from Unitronics can replace a PID controller and save a lot of work.
With its embedded HMI and direct temperature measurement inputs, a Jazz PLC from Unitronics can replace a PID controller and save a lot of work.

The JZ10-11-UA24 offers two thermocouple/PT100 inputs, two analog inputs and two analog outputs; JZ-11-UN20 offers one thermocouple/PT100 input and one analog input. Both models include additional digital I/Os—total I/O count reaches up to 24 onboard I/Os.

All Jazz models include four auto-tune PID loops. PID can be set using the onboard temperature/analog inputs, and the analog or PWM (pulse width modulation) outputs (all onboard transistor outputs can function as PWM outputs). Jazz also features a full-function HMI with a two line LCD text display that shows up to 60 user-designed screens, and a 16-key keypad. The multilingual display supports over 15 languages, and 20 graphic symbols, including the degree sign.

Jazz’s control and communication options make it a step up from a “smart-relay”: 24K (virtual) of Ladder Logic enables flexibility and functionality. Software functions include interrupt, loops, math, store & compare. Communication options include SMS messaging, Modbus networking, and PC access via Modbus or OPC.

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