Download document () of 20

Understanding pilot devices

What are pilot devices?

Today, machines often perform more than function. This is where pilot devices come in. Through pilot devices, workers can interact with the machine’s operation.

Pilot devices communicate information both directions – from a human to the machine (turning it on and off), and then from machine to the human (current state of the machine).

Pilot devices consist of pushbuttons, selector switches, toggle and rocker switches, indicating lights and signal towers. They can be found in any application – residential, commercial and/or industrial – anywhere there is a need to operate and/or talk to a machine.

vacuum-switches.jpg

Types of pilot devices

There are a wide range of pilot devices available depending on the application. These include:
pushbuttons.jpg

Pushbuttons

stack-lights.jpg

Stacklights

selector-switch.jpg

Selector switches

toggle-switch.jpg

Toggle switches

indicator-lights.jpg

Indicating lights

rocker-switch.jpg

Rocker switches

What is a pushbutton?

A pushbutton is a type of pilot device that acts as a simple switch mechanism for controlling some aspect of a machine or a process. 

Pushbuttons are utilized in calculators, computers and kitchen appliances. Within industrial and commercial applications, pushbuttons can be linked together so the act of pushing one button causes another one to be released.

Pushbuttons are color coded to associate their color with their function to make it easier for the operator. Commonly used colors are RED for STOP and GREEN for GO.

Pilot device sizes

The size of a pilot device is measured by the diameter of the hole the device is mounted in. Here are three typical sizes that cover most applications:

  • 16 mm – Very small market
    Common in light commercial equipment
  • 22 mm – Sized to meet the largest market segments
    Most common choice for OEMs
  • 30 mm – Sized to meet the largest market segments in North America
    Most often used in heavy-duty applications
press brake conveyor system push buttons

Pushbutton styles

extended-pushbutton.jpg
Extended
An extended button is raised higher off the panel than other buttons.
flush-pushbutton.jpg
Flush
The button is flush with its housing. Pressure must be applied to actuate. Not easily bumped to changed state.
guarded-pushbutton.jpg
Guarded
One step further on protection by having a metal guard around the actuator position of the button.
mushroom-pushbutton.jpg
Mushroom
Very easy to actuate due to the design. Mostly used for Stop and Emergency Stop buttons.
twist-to-release-pushbutton.jpg
Twist to release Emergency Stop
This button needs to be pushed twisted to release. Additional effort forces a more active decision.
key-release-pushbutton.jpg
Key release Emergency Stop
This is a maintained contact button that you push in and need a key to release. Often used for safety reasons.
indicator-light-pushbutton.jpg
Indicating light
Gives the user visual indication of machine status or alarm conditions.
multifunction-operator-pushbutton.jpg
Multifunction operator
Used when space is premium and more than one function is required.
push-pull-operator-pushbutton.jpg
Push-pull operator
This must be physically pushed or pulled to change its status.

What are selector switches?

Selector switches provide flexible control options in a minimal amount of space. They perform multiple functions and only inhabit the space of a typical pushbutton.

The major difference between a selector switch and a pushbutton is that, while a pushbutton has a plate that pushes both contactor plunges at the same time, a selector switch has a rotating piece with ridges and flats on it, allowing the operator to actuate the plungers independently.

Selector switches are usually the preferred pilot device when a maintained contact state is needed.

What are indicating lights?

Indicating lights tell the worker what the machine is doing or failing to do. Light units are behind the panel to hold the lamp and provide wiring terminals. Together they indicate what the machine is doing.

Think of it like this…a pushbutton or selector switch is the light switch in your kitchen. They are where you make the decision to turn the light on. Indicating lights are simply the light that turns on. When the light is connected to a machine process, and the light is on, the machine is telling you that it is working.

child turning off light switch

What are signal towers?

Signal towers or stacklights are a special form of indicating light. Instead of being mounted on the front of the panel, they are a mini-tower of indicating lights usually mounted on top of a machine to provide 360-degree visibility with important information regarding a machine or process state.

They are easily assembled and can include constant, flashing or strobe light indication as well as monotonal, bi-tonal and intermittent audible alarms. Several lamp, color and mounting options further enhance signal tower versatility.

Brake Conveyor stack lights

What are toggle switches?

Toggle switches are to be used when a customer needs a rugged actuated switch with proven durability. Some toggle switches prevent accidental or unintentional operations with a lever lock that requires pull-out for operation. Other toggle switches have an unique positive center stop design feature that has widespread acceptance for motor reversing and speed control application.
toggle-switch2.jpg

What are rocker switches?

Rocker switches are used in applications where there is a need for lighting or graphics to show:

  • Function
  • Position
  • Status
  • Location

Rocker switches have a very clean and polished look, therefore, rockers are ideal for applications in which aesthetics are important.

NGR laser etch rocker device

Specialty operators include

  • Joystick – Extends outwards and often corresponds to the direction of movement sought, therefore, it is easy and intuitive to use
  • Acoustic devices – Buzzers or other audible on a panel to act as an audible alarm
  • RJ45 and USB adapters – Link a device inside the panel to the person outside – useful for firmware/software updates or downloads without having to open the panel
  • Quad pushbuttons – Multi-direction or start/stop/reversing/joy
  • Double pushbuttons – Start/Stop – most common
  • Potentiometers – A dial that adjusts the amount of voltage sent to a machine.
Double pushbutton