PLC Simulator
Runnable electrical diagnosis case

Measure a 120 VAC Control-Transformer Secondary

A contactor will not energise and an authorised technician must prove whether 120 VAC control power is present at the transformer secondary. The exercise grades the complete measurement plan—state, mode, placement, range and expected evidence—before a tool is applied.

10 minutes Electrical apprentices, industrial maintenance technicians and controls learners

Follow the workflow

Learn one step, use the product, inspect the evidence.

01

State the troubleshooting question first

Select AC voltage and parallel placement while preserving the energised-work boundary. One measurement should answer one branch of the fault tree; collecting numbers without a decision rule creates more ambiguity.

Do this in the product

Open the registered Control transformer secondary case and leave the answer fields untouched until you can justify each choice.

Open the exercise
02

Establish the electrical state

The case expects “energised authorised”. Resistance and continuity need isolation and prove-dead evidence; live voltage or current needs competent authorisation and rated equipment.

Do this in the product

Choose the circuit state before selecting a meter function so the safety boundary drives the method.

Open the exercise
03

Choose mode, placement and range as one plan

The registered plan uses ac voltage mode, parallel placement and a 600 full-scale range. These choices must agree electrically.

Do this in the product

Submit the plan and use the individual server checks to find the first unsafe or non-diagnostic choice.

Open the exercise
04

Predict evidence and the next branch

The expected evidence is 120 VAC. A different reading is useful only when it leads to a documented next check rather than an immediate component replacement.

Do this in the product

Save the graded result for a portfolio record or assign it through a paid team training path.

Open the exercise

Core concepts

Know what the evidence means.

The simulator creates a repeatable result; these concepts make that result transferable to real vendor software and supervised practical work.

Question-led measurement

The expected reading and next action are written before the probes move, reducing random fault finding.

Electrical placement

Voltage is measured across two points, current through a series path and resistance only on an isolated circuit.

Instrument limitation

A multimeter result is one item of evidence. It does not replace isolation, category ratings, process knowledge or specialised test instruments.

Common mistakes to avoid

  • × DC mode can display a misleading value and continuity mode must never be used on the energised secondary.
  • × Moving a lead between voltage and current ports without rechecking the selector and fuse.
  • × Treating one plausible reading as proof that every upstream and downstream condition is healthy.
  • × Performing physical work from a generic online example instead of the site procedure and equipment documentation.

Continue in the workspace

Turn this tutorial into retained training evidence.

Run the foundation exercise publicly, then use a subscription for advanced challenges, saved configurations, full attempt history, sharing, assigned paths and team reporting.

Technical reference questions

Questions before you continue.

It expects ac voltage mode, parallel placement and the documented 600 range under a energised authorised state.