Pulse Relay

The Pulse Relay node sends 1 to the output when the Set input is set to 1 and sends 0 to the output when the Reset input is set to 1.
When both Set and Reset are equal to 0, the previous state of the output is maintained.

Whenever the Trigger input receives a rising edge, the Set and Reset inputs are ignored and the output state is toggled.

The Behaviour property determines whether Set or Reset must be dominant when both of them are equal to 1.

The Pulse Relay combines the behaviour of a latching relay with a toggle command.

The node can therefore be controlled in two different ways:

• directly through Set and Reset;
• by toggling the current output state through Trigger.

When no Trigger event occurs, the Set/Reset logic is:

• if Set = 1 and Reset = 0, the output becomes 1;
• if Set = 0 and Reset = 1, the output becomes 0;
• if Set = 0 and Reset = 0, the previous output state is maintained;
• if Set = 1 and Reset = 1, the resulting state depends on the configured Behaviour property.

The Trigger input reacts to a rising edge:

0 → 1

Whenever a rising edge is detected, the current output state is toggled.

Conceptually:

Output = NOT Output

Therefore:

• if the current output is 0, a Trigger event changes it to 1;
• if the current output is 1, a Trigger event changes it to 0.

Assume the initial state is:

Output = 0

and Set and Reset are not connected.

Each rising edge on Trigger produces the following sequence:

The node therefore converts repeated pulse events into a bistable toggle state.

The Set and Reset inputs can be used to force a defined output state.

When:

Set = 1

and:

Reset = 0

the output becomes:

1

When:

Set = 0

and:

Reset = 1

the output becomes:

0

When both inputs return to 0, the previous output state is maintained.

The Behaviour property defines what happens when both Set and Reset are equal to 1 at the same time.

The two possible behaviours are conceptually:

• Set dominant
• Reset dominant

When Set is dominant:

When both inputs are active, activation has priority.

When Reset is dominant:

When both inputs are active, deactivation has priority.

The Trigger command has a special role because it toggles the output independently from the Set/Reset logic.

For example, assume:

Output = 0

and:

Set = 1

If a rising edge is received on Trigger, the current state is toggled according to the Trigger command and the Set/Reset inputs are ignored for that event.

This makes Trigger suitable for push-button style control.

A push button sends a short pulse every time it is pressed.

The pulse is connected to Trigger.

Starting from:

Output = 0

the sequence becomes:

• first press → Output = 1
• second press → Output = 0
• third press → Output = 1

This allows a momentary push button to control a persistent ON/OFF state.

The Pulse Relay can also combine toggle control with explicit Set and Reset commands.

For example:

• a local push button is connected to Trigger;
• a central ON command is connected to Set;
• a central OFF command is connected to Reset.

The push button can toggle the current state locally, while Set and Reset can force a specific state when required.

The Pulse Relay is useful whenever a pulse command must control a persistent digital state.

Typical applications include:

• converting a push-button pulse into an ON/OFF toggle;
• controlling lights from momentary buttons;
• maintaining a digital state after a pulse;
• combining local toggle commands with centralized Set and Reset commands;
• implementing bistable control logic;
• controlling devices with pulse-based commands.

The Pulse Relay can be tested using the Logic Module simulation tools.

A typical test procedure is the following:

• start with Set = 0, Reset = 0 and Trigger = 0;
• generate a rising edge on Trigger and verify that the output toggles;
• return Trigger to 0;
• generate another rising edge and verify that the output toggles again;
• set Set = 1 and verify that Output = 1;
• return Set to 0 and verify that the output state is maintained;
• set Reset = 1 and verify that Output = 0;
• test Set = 1 and Reset = 1 and verify the configured Behaviour;
• generate a Trigger rising edge while Set or Reset is active and verify that the Trigger event takes priority.

• Trigger reacts to rising edges, not to the duration of the signal.
• The Trigger input must return to 0 before another rising edge can be detected.
• Each Trigger rising edge toggles the current output state.
• Set and Reset are optional.
• If Set and Reset are not connected, Trigger alone can control the output.
• The Behaviour property is relevant when Set and Reset are both equal to 1.
• Use Set or Reset when a defined output state must be forced.
• Use Trigger when a pulse must toggle the current state.

• Logic Module
• Logic Module - Simulation management
• Latching Relay