Software of Programmable Controllers

Slovak University of TechnologyFaculty of Material Science and Technology in Trnava

2007

Programmable controller KRGN 90 8 - loop controller HW configurable I/O signal more than 40 pre-programmed functions operator panel

operator interface engineering functions

4 displays to monitor a controlled processes communication protocol...

KRGN 90 - operator interface

Displays

DATA - VALUE Set Point PROCESS OUTPUT ALARMS

KRGN 90 - operator interface

Keys

Set Point MAN, AUTO, CAS Man Reset PP, II, DD ACK

KRGN 90 - eng. functions

Displays Object - step - function - data - value

AI configuration CONF / AUX - ANAL

Loop configuration CONF / AUX - LOOP

INS - RPL - DEL

Analogue input configuration

CONF - ANAL- AInn FNC 01 - Q1, Q2, Q3, Q4...

AUX - ANAL - Ainn DFIL, ISCL, ISCH IALL, IALH, ISFL, ISFH, SAFE

ANAL - Ainn AI type assignment to the physical AInn

Loop configuration CONF - LOOP- l

FNC 10, FNC 20, FNC 55

AUX - LOOP - l SCAN, OLIL, OLIH, OGRL, OGRH LSCL, LSCH, GRAD PALL, PALH, DALL, DALH DINL, DINH, GAPL, GAPH...

LOOP ON / OFF

Loop program structure Controller KRGN 90 has 8 LOOPs

Loop has 20 program STEPs maximum

Program step consists one function FNCnn

Function has questions Q1,Q2, Q3,...

FNC 01 - AI processing

Purpose: The unified analogue signal transformation to digital representation in e.u. and primary input variable processing.

Q1 – a type of current unified input signal

Q2 – linearisation type

Q3 – binary output for technological alarm signalisation

Q4 – safety alarm signalisation

FNC 10 - step signal specification

An value assignment to the real and logical part of program step output, where the function FNC 10 is configured.

Q1 – real part of the program step value

Q2 – logical part of the program step specification

FNC 20 - PID function

The ideal paralel type of a PID algorithm as a sum of the proportional, integral and derivative part of a control action.

Q1– the type of the set point processing when a loop is switched from MAN to AUTO mode.

Q2 – control action direction

Q3 – loop mode after controller restart

FNC 20 - PID functionFNC 20 continued:

Q4 – type of the derivative part of control action

Q5 – binary variable address for process variable alarm

Q6 – binary vaariable address for deviation alarm

Q7 – control action computation type

FNC 21 – Set Point computation for cascade loop

A computation of the set point for a slave loop in cascade mode.

A set point of the cascade loop is computed according the expression

ZHCAS = RATIO*INPUT+BIAS

Q1 – signal source specification

FNC 22 – Auto RATIO

On line computation of the slave loop RATIO for a bumpless switching the AUTO mode to the CAS one

INP

BIASZHCASRATIO

Q1 – signal source specification

FNC 23 – Auto BIAS

On line computation of the slave loop BIAS for a bumpless switching the AUTO mode to the CAS one

Q1 – signal source specification

INPUT*RATIOZHCASBIAS

FNC 24 - SP computation for slave loop

A set point computation for a cascade loop, when the limits of this set point are given.

Q1 – loop number

LSCLLSCH*n

DOUT1n

ZHCASn

ZHCAS

FNC 30- arithmetic operations

Arithmetic operations: sum, difference, multiplication and division.

Q1 – the second operand

Q2 – type of arithmetic operation

Q3 – order of operands

FNC 50 – Dynamic signal compensation

Dynamic compensation of a signal by the block LEAD/LAG of 1st order.

Q1 – lead time constant in the interval 0 to 99999 sec.

Q2 – lag time constant in the interval 0.5 to 99999 sec.

isT1dsT1

F(s)

FNC 51 – Dead Time Block

A delay of a main value signal at a specified time.

Q1 – time delay in the interval 0.5 to 99999 sec.

sDeF(s)

FNC 55 – D/A conversion

A conversion of a control action value to the corresponding analogue unified signal.

Q1 – type of analogue current unified signal

Q2 – signal specification

Auxiliary parameters for AI

DFIL – the time constant of 1st. order digital filter

ISCL – input scale lower

ISCH – input scale upper

IALL – lower limit for technological alarm

IALH – upper limit for technological alarm

Auxiliary parameters for AI

ISFL – input safety lower value

ISFL – input safety lower value SAFE - safety/ default value of input signal

Auxiliary parameters for LOOP

SCAN – program loop execution scan period

OLIL – lower limit of control action

OLIH – upper limit of control action

OGRL – maximum rate of valve closing rate during one scan period

OGRH – maximum rate of valve opening rate during one scan period

Auxiliary parameters for LOOP continued

GRAD – maximum rate of set point change during one

scan period

LSCL – lower limit of set point

LSCH – upper limit of set point

PALL – lower limit of process variable alarm

PALH – upper limit of process variable alarm

DALL – lower limit of deviation alarm

DALH – upper limit of deviation alarm

Auxiliary parameters for LOOP continued

DINL – deviation lower limit indicated on the bargraph

DINH – deviation upper limit indicated on the bargraph

GAPL – lower hysteresis band for control action execution

GAPH – upper hysteresis band for control action execution