What do the control modes on Automation Service 43AP pneumatic controller mean?

Pneumatic Instrumentation from Automation Service

The 43AP Controller is a type of process controller that can be used in various industrial applications to regulate a process variable, such as temperature, pressure, level, or flow rate. The controller has several different control modes, each of which tune, or condition the controller to operate in a different way to achieve a desired setpoint. 

Here are some of the control modes on the 43AP Controller and their meanings: 

1. Proportional (P) control mode: In this mode, the change in controller output is proportional to the error in, or difference between, the process variable and the setpoint. The larger the error, the larger the change in output signal. 

1. Proportional + Integral (PI) control mode: This mode adds an integral component to the Proportional control mode, which helps to reduce any steady-state error that may exist. The integral mode calculates the error between the process variable and the setpoint repeatedly over a preset time period and adjusts the output signal proportional to the error. 

1. Proportional + Integral + Derivative (PID) control mode: This mode adds a derivative component to the P + I control mode, which helps to improve the controller’s response time to changes in the process variable. The derivative mode calculates the rate of change of the error and adjusts the output signal accordingly. 

1. On-Off control mode: In this mode, the controller output switches between two states, either fully on or fully off, based on whether the process variable is above or below the setpoint.  

1. Differential Gap Mode: This mode is like On-Off in terms of the controller switching between two states of fully on or fully off, but the difference being a differential gap, or dead band.  The dead band is set up by adjusting an upper control point and a lower control point, the points at which the controller output changes.  

1. Automatic Shutdown Mode: Automatic Shutdown Mode is also similar to On-Off Mode, except when the controller output changes when the setpoint is reached, it will not switch back to the other state even if the process variable is below the setpoint.  Operator intervention is required to manually reset by pressing a pushbutton on the controller. 

These control modes are used to regulate the process variable and ensure that it remains within a specified range of values. The choice of control mode depends on the characteristics of the process being controlled and the desired control performance.