Pressure switch
From FIRSTwiki
A pressure switch is a pneumatics switch whose state changes depending on the pressure.
Contents |
Data
Sends a digital signal. The two terminals are shorted together when the pressure is greater than 95psi after hitting a peak of 115psi. The terminals are disconnected when the pressure is less than 115psi after dropping below 95psi.
Connections
Air
Connects to the system via a 1/8" NPT thread on the bottom.
Signal
Two terminals on the top that are connected to a digital input on the robot controller, connecting on the black and white wires.
Current Product Info
Supplier
Supplied by [The Nason Company].
Model Number
SM-2B-115R
Programming
The Robot Controller needs to check the pressure switch and react accordingly by applying power to the compressor when needed.
Default Code
Note that if you have not modified the code in your Robot Controller, you may connect the pressure switch to digital input 1, with the signal wire connected to one terminal of the switch and the black ground wire connected to the other terminal. Connect the Spike Relay with compressor attached to relay output 8. The controller should turn the compressor on when needed, and off when not.
easyC PRO
Use the "Pressure Switch" block under "Outputs". When you drag the block into your code, a window will pop up asking which input the pressure switch is on. Also in this window is the relay output you connect the compressor to. Select the correct channels in this window. It will only allow you to use pins that are configured as inputs; to configure others, go to the Main function of your project and double-click Config. Under "DIGITAL IN/OUT", click the desired pin's arrow--it should point to the pin for an input. Once you have placed the Pressure Switch block, the code automatically checks the pressure switch every 500 milliseconds (1 millisecond = 0.001 second; 500 milliseconds = 1/2 second) and switches the relay on if needed.
MPLAB
First, you need to make sure the digital IO pin you want to use is configured as an input. If you are using the IFI base code, inside the user_routines.c file, there is a function called User_Initialization(). At the top of that function, there is a series of lines setting the port direction of each digital input. Make sure that the pin you wish to use is being set equal to INPUT--if you are using digital input 5, for example, you need to be sure digital_io_05 is set to INPUT.
Once the port direction has been set to input, you need to put a line of code in a function that is called repeatedly; Process_Data_From_Master_uP() would be an OK place. The compressor output relay needs to be set to the opposite of the input--the pressure switch reads "1" when the tanks are full, and "0" when the tanks are low/empty. So the line of code would look like
relay#_fwd = !rc_dig_in##;
where the # signs are replaced with the appropriate channel numbers.
The compressor should then turn on when it is needed, and off when it is not.
| Pneumatics Parts: Cylinder | Solenoid | Compressor | Storage tank | Rotary actuator | Pressure regulator | Pressure switch |
