FieldengInstrumentation & Controls
PID Output (one step)
One discrete PID step. Not a running controller. Simple anti-windup holds the integral when the output saturates.
Instrumentation & Controls
One discrete PID step. Not a running controller. Simple anti-windup holds the integral when the output saturates.
App id: INST-33. Reference version 1.0.
How to fill it
Fill the inputs. The tool shows the outputs.
On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.
Formula
u = Kp [ e + (dt/Ti) e + Td (e − e_prev)/dt ]Inputs
| Name | Unit |
|---|---|
| Setpoint | 1 |
| Process variable | 1 |
| Kp | 1 |
| Sample interval dt | s |
| Integral time Ti (optional) | s |
| Derivative time Td (optional) | s |
| Previous error (optional) | 1 |
| Integral state (optional) | 1 |
| Output minimum (optional) | fraction |
| Output maximum (optional) | fraction |
| Action (0=reverse, 1=direct) (optional) | 1 |
Outputs
| Name | Unit |
|---|---|
| Limited output (hero result) | % |
| Unbounded output | 1 |
| P term | 1 |
| I state | 1 |
| D term | 1 |
| Error | 1 |
Diagnose
Observations are context. They do not pass or fail a structure. See Diagnose.
| When | Observation | Severity |
|---|---|---|
Unbounded output ≠ Limited output | PID output limited | caution |
Assumptions
- Leave Ti/Td blank to disable those terms. Default limits 0–100%. Default reverse action.
- When the unbounded output is outside the limits, the integral is held at the previous state.
Provenance
- ISA-style positional form. Derivative on error, not PV. Derivative noise is not filtered.