Signals
What this tool does
Expected 4–20 mA, 1–5 V, or 0–10 V at each test percent, with a tolerance band. This page says what the tool is for, in plain language. The working formula stays on the signed-in tool.
When to use it
Open Loop check-out when this is the job: Expected 4–20 mA, 1–5 V, or 0–10 V at each test percent, with a tolerance band. That is usually a loop check, a range change, or a signal that does not match the panel.
Step-by-step
- Open Loop check-out from the tool list.
- Fill Analog range, Transfer, Test percent, Measured signal from the instrument, the drawing, or the job record. Use the unit shown beside each field.
- Fill the remaining fields the same way. Skip a field only when the screen marks it optional.
- Run Calculate when that control is on the page, then read every result row and any warning.
- Check the result against the site procedure and the manufacturer data before you change a range, a wire, a setpoint, or a weight.
- This help page is public. Opening the tool still requires a Pro session.
Inputs
- Analog range
- Choose the Analog range that matches the instrument, the drawing, or the job. Choices include 4–20 mA, 1–5 V, 0–10 V.
- Transfer
- Linear uses the span directly. Square root is for a differential-pressure flow signal.
- Test percent
- Test percent is the value you read from the instrument, the drawing, or the job record. Enter it in %.
- Measured signal
- Measured signal is the value you read from the instrument, the drawing, or the job record.
- Tolerance
- Tolerance is the value you read from the instrument, the drawing, or the job record. Enter it in % of span.
- LRV
- Lower range value. The process reading at the bottom of the calibrated span.
- URV
- Upper range value. The process reading at the top of the calibrated span.
- Engineering unit
- Engineering unit is a name or a note for this sheet. It does not change the check by itself.
Results
- Result
- The reported value for Loop check-out. Use the unit printed on that row.
- Warnings
- A warning means an entry is incomplete or outside what this tool will stand behind. Recheck the inputs and the site procedure.
Common mistakes
- Swapping the lower range and the upper range, or typing the live reading into a range field.
- Treating a square-root flow signal as if it were a linear span.
- Changing a range while a warning is still on the screen.
- Do not treat a result from Loop check-out as a substitute for the site procedure or the manufacturer data.
Standards references
These are the standards and public references named on this tool. Clause numbers appear only when the catalog already cites them.
- ISA analog span practice for 4–20 mA, 1–5 V, and 0–10 V
- ISA-50.1: 4–20 mA through 250 Ω is 1–5 V
- Bernoulli relation for square-root differential-pressure flow
Offline and access
This engine can run offline after the server has cached it for the signed-in account.
A free session can read this help page. The tool card shows the name and the short summary. Opening the tool requires Pro.