Electrical
What this tool does
Maximum loop resistance from the supply, and the HART resistance window. 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 load and HART resistance when this is the job: Maximum loop resistance from the supply, and the HART resistance window. That is usually a loop, a conductor, a raceway, or a barrier you are about to accept or reject.
Step-by-step
- Open Loop load and HART resistance from the tool list.
- Fill Supply, Transmitter minimum, Installed loop resistance from the instrument, the drawing, or the job record. Use the unit shown beside each field.
- 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
- Supply
- The DC supply voltage at the loop or the transmitter.
- Transmitter minimum
- The lowest voltage the transmitter is allowed to see while it is still in spec.
- Installed loop resistance
- Installed loop resistance is the value you read from the instrument, the drawing, or the job record. Enter it in Ω.
Results
- Result
- The reported value for Loop load and HART resistance. 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
- Using the wrong metal, the wrong insulation column, or a one-way length where the circuit is a round trip.
- Comparing barrier and device parameters that are not from the same certificate columns.
- Applying a fill or ampacity table to a raceway or a wire the table does not cover.
- Do not treat a result from Loop load and HART resistance 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.
- Ohm's law on a 4–20 mA loop
- HART loop-resistance window (public HART documentation)
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.