Control Logic Block Library

Signal inputs

Input Block

The input block represents an incoming field signal that brings a discrete process condition into the control logic.

Signal inputs

Mini Switch

The mini switch represents a maintained operator or field switch that holds its state until it is changed again.

Signal inputs

Pulse Switch

The pulse switch generates a brief momentary signal so a command can trigger logic without remaining latched on.

Signal inputs

Clock

The clock block provides a repeating timed signal that can be used to trigger periodic actions or pace sequence logic.

Signal outputs

Output Block

The output block represents a driven logic output used to command an external device or pass an active control state onward.

Signal outputs

Light Bulb

The light bulb symbol indicates that a circuit state is active and is typically used to show status, run, or alarm conditions.

HMI / SCADA elements

Manual Valve

The manual valve symbol represents a hand-operated valve whose process state is set by an operator rather than by a driven output.

HMI / SCADA elements

Auto Valve

The auto valve symbol represents an actuated valve whose open or closed state is controlled directly by the automation logic.

HMI / SCADA elements

Control Valve

The control valve symbol represents a modulating final element that adjusts process flow in response to a control signal.

HMI / SCADA elements

Pump

The pump symbol represents a driven process unit that starts or stops to move fluid when the logic issues a run command.

IEC 61131-3

AND Gate

The AND gate only produces an active output when every required input condition is true at the same time.

IEC 61131-3

OR Gate

The OR gate turns on when any one of its valid input conditions is true.

IEC 61131-3

NOT Gate

The NOT gate inverts the incoming state so a true signal becomes false and a false signal becomes true.

IEC 61131-3

NAND Gate

The NAND gate gives an inactive result only when all of its required inputs are true together.

IEC 61131-3

NOR Gate

The NOR gate becomes active only when every monitored input remains false.

IEC 61131-3

XOR Gate

The XOR gate turns on when its compared inputs differ, making it useful for change or mismatch detection.

IEC 61131-3

Active Count Comparator

The active count comparator evaluates how many inputs are on and compares that total against a required threshold.

IEC 61131-3

Edge Detector

The edge detector produces a short event when it sees a state transition rather than a maintained condition.

IEC 61131-3

Timer

The timer block delays or measures an action over time so logic can react after a configured interval.

IEC 61131-3

Counter

The counter block tracks events or pulses and changes state once the configured count condition is met.

IEC 61131-3

Digital Two-to-One Selector

The digital two-to-one selector routes one of two discrete input paths through to the output based on a select condition.

IEC 61131-3

Analogue Four-to-One Selector

The analogue four-to-one selector chooses one of four analogue values and passes the selected signal onward.

IEC 61131-3

Arithmetic

The arithmetic block performs numerical operations so control logic can calculate derived process values.

Control elements

PID Controller

The PID controller continuously adjusts its output to reduce the error between a measured value and a target setpoint.

Control elements

Plant Delay

The plant delay block represents lag between an applied control action and the visible response from the process.

Control elements

Clamp

The clamp block prevents a signal from moving above or below defined limits.

Control elements

Rate Limit

The rate limit block restricts how quickly a value can rise or fall to smooth aggressive changes.

Control elements

Disturbance

The disturbance block injects an external upset into the model so the control strategy can be tested against changing conditions.

Control elements

Disturbance Valve

The disturbance valve block models a valve-driven upset so flow changes can be introduced into the process response.

Control elements

Noise

The noise block adds random variation to a signal so measurements and control can be tested under less ideal conditions.

Control elements

Low Pass

The low pass block smooths a signal by filtering out rapid changes and high-frequency noise.

Control elements

Error Scope

The error scope block visualises how error changes over time so tuning and dynamic behaviour can be reviewed.

Control elements

Step

The step block applies a sudden change to a signal so the process response can be examined.

Control elements

Hysteresis Comparator

The hysteresis comparator changes state using separated switching thresholds so noisy signals do not chatter.

Control elements

Scale

The scale block converts one numerical range into another so raw values can be mapped into engineering units.

Control elements

Function

The function block applies a defined mathematical or logical transformation to produce a calculated output.

Basic shapes and labels

Basic Shapes

The basic shapes image shows the general-purpose graphic building blocks used to assemble custom layouts, panels, and screen elements.