quiz 4.docx

**[The Basic Difference Between Analog and Digital I/O]** - Analog I/O is used when you need to detect or control an event which involves a range of values. - Digital I/O is used when you need to detect or control an event which is binary (yes/no, on/off). #### **[Analog Input Devices...

**[The Basic Difference Between Analog and Digital I/O]** - Analog I/O is used when you need to detect or control an event which involves a range of values. - Digital I/O is used when you need to detect or control an event which is binary (yes/no, on/off). #### **[Analog Input Devices]** - **Force Sensors** --- [[Either attached to the robot]](http://robotiq.com/products/robotics-force-torque-sensor/) or fixed elsewhere, these measure the magnitude of forces applied to them as an analog value. - **Potentiometers** --- These are used for a variety of applications, from simple control knobs to detecting the position of a motor. - **Light sensors** --- These can be single or multi-color sensors. They detect the amount of light hitting them and are used in photoelectric part detection sensors to measure the distance to objects. - **Vision sensors** --- These are analog input devices as they measure the amount of light hitting a sensor. ### **[Analog Output Devices]** - **Conveyor belt motor speed** --- For advanced conveyor applications, the speed of the belt can be integrated into the robot controller. - **Analog control valves** --- When a fluid is involved in a process, analog control valves are a way to precisely control the amount of fluid which is released. These are used in hydraulics. - **Lamp brightness** --- The brightness of an LED or lamp can be set precisely. ### **[Digital Input Devices]** - **Limit switches** --- Detecting when a safety door is opened or when a robot reaches an external limit. - **Basic part detection sensors** --- Detect when an object is present.  - **Single-beam laser safety sensors** --- Used in safety curtains, these sensors detect when a laser beam is broken, to indicate that someone has entered an unsafe area. - **Push buttons** --- A simple but important sensor. Push buttons are an effective way to start or stop a pre-programmed sequence. ### **[Digital Output Devices]** - **Relays** --- These are electronically controllable switches, which allow high-power circuits to be operated by low-power electronics. - **Warning lights** --- Often used in circuits with safety sensors, these can be switched on to show that a robot is in operation and workers should not enter the area. - **Conveyor on/off** --- A simpler way of controlling conveyor belts than speed control is just to allow the robot controller to activate the belt. - **Audio alarms** --- Like warning lights, these are often used to indicate that a safety-related event has occurred.