PID-Py 0.1.1

Simple (but complete) PID controller in Python

PID_Py

PID_Py provide a PID controller wrote in Python. This PID controller is simple to use, but it's complete.

Installation

python3 -m pip install PID_Py

Usage

Minimum usage

from PID_Py.PID import PID

# Initialization
pid = PID(kp = 0.0, ki = 0.0, kd = 0.0)

...

# PID execution (call it as fast as you can)
command = pid(processValue = feedback, setpoint = targetValue)

In this usage the PID as no limitation, no history and the PID is in direct action (Error increasing -> Increase output)

Indirect action PID

If you have a system that required to decrease command to increase feedback, you can use indirectAction parameters.

from PID_Py.PID import PID

# Initialization
pid = PID(kp = 0.0, ki = 0.0, kd = 0.0, indirectAction = True)

...

# PID execution (call it as fast as you can)
command = pid(processValue = feedback, setpoint = targetValue)

Limiting output

If your command must be limit you can use outputLimits parameters.

from PID_Py.PID import PID

# Initialization
pid = PID(kp = 0.0, ki = 0.0, kd = 0.0, outputLimits = (0, 100))

...

# PID execution (call it as fast as you can)
command = pid(processValue = feedback, setpoint = targetValue)

By default the value is (None, None), wich implies that there is no limits. You can activate just the maximum limit with (None, 100). The same for the minimum limit (-100, None)

Historian

If you want to historize PID values, you can configure the historian to record values.

from PID_Py.PID import PID
from PID_Py.PID import HistorianParameters

# Initialization
historianParameters = HistorianParamters.SETPOINT | HistorianParameters.PROCESS_VALUE
pid = PID(kp = 0.0, ki = 0.0, kd = 0.0, historianParameters = HistorianParameters)

...

# PID execution (call it as fast as you can)
command = pid(processValue = feedback, setpoint = targetValue)

...

# PID Historian
import matplotlib.pyplot as plt

plt.plot(pid.historian["TIME"], pid.historian["SETPOINT"], label="Setpoint")

plt.plot(pid.historian["TIME"], pid.historian["PROCESS_VALUE"], label="Process value")

plt.legend()
plt.show()

In the example above, the PID historian records setpoint, processValue and time. Time is the elapsed time from the start. After that a graphic is draw with matplotlib