Fuji Electric Frenic Eco Series Setup

PID SET UP WITH FRENIC Eco series inverter.
1. Introduction.
This document describes briefly how to set up the FRENIC Eco series inverter to
implement a PID control, for example, a pressure control with a pump, where the
pump is moved by a motor controlled by a FRENIC Eco inverter.
2. Preparation.
Before setting up a PID controller few items have to be checked. As an example we
will describe a set up for controlling pressure.
• Is the sensor capable of sensing the expected range?
When we want to control the pressure in a system to 2 Bar, the sensor must
be capable of measuring more. Preferably 1.5 times more, i.e. 3 Bar.
• Does it have an output signal that can be connected directly to the FRENIC
Eco input?
FRENIC Eco has inputs for 0-10 V and 4-20 mA signals.
3. PID Basics.
3.1 PID Basic Concept.
A PID regulator is a control structure that will try to control a certain magnitude
(pressure, flow rate, temperature, ...) to a desired value, which is called PID
command (or set-point) value. To do so this structure needs information of the actual
status of the system by means of the proper measurement device (pressure, flow or
temperature sensor). This signal is called the PID Feedback. This control structure
normally has three control actions: Proportional (P), Integral (I) and Derivative (D)
that have to be tuned according to the real system.
What happens in this picture?
PID SET UP WITH FRENIC Eco series inverter.
Figure 1. PID control structure diagram.
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