This example introduces you to the cyclic programming with RevPiModIO and the
cycleloop(...)! The program also uses the handlesignalend(…) function to catch the “end of program” signal and exit the program cleanly.
# -*- coding: utf-8 -*- import revpimodio2 def cycleprogram(cycletools): """This function is automatically executed every IO cycle.""" # Write the value of the first input to the first output rpi.io.O_1.value = rpi.io.I_1.value # If second input is True, always start switch-off timer if rpi.io.I_2.value: # Set off delay for 20 cycles cycletools.set_tofc("t_20", 20) # Write the value of the switch-off delay timer in the second output rpi.io.O_2.value = cycletools.get_tofc("t_20") # A2 flash every 10th cycle if cycletools.flag10c: rpi.core.A2 = revpimodio2.GREEN else: rpi.core.A2 = revpimodio2.OFF def programend(): """This function does cleanup work before the end of the program.""" # Switch off LED A1 on the Core rpi.core.A1 = revpimodio2.OFF # Instancing RevPiModIO with automatic process image synchronization, # the configuration is automatically read from piCtory. rpi = revpimodio2.RevPiModIO(autorefresh=True) # Manage signals for "end of the program" by RevPiModIO. Pass a cleanup # function, which is executed at program end (Ctrl + C / SIGTERM). rpi.handlesignalend(programend) # Switch on green LED A1 on the Core rpi.core.A1 = revpimodio2.GREEN # Start cyclic processing of the "cycleprogram" function. print("Go into cycleloop") rpi.cycleloop(cycleprogram) print("Left cycleloop")
The standard cycle time is 50 milliseconds. It can be changed when calling cycleloop function via
rpi.cycleloop(cycleprogram, cycletime=40). If the updating of the IOs including the execution of the cycle function exceeds this time, warnings are issued.
Our piCtory configuration for this example includes a RevolutionPi Core and on the right a DIO module, which is set with Inputs: 34 / Outputs: 32. The names “I_1”, “I_2”, “O_1”, “O_2” must be specified in the “Value Editor”.