Electrician Red Seal · Question
A production line operator reports that a valve controlled by a PLC output is not opening, even when the HMI indicates the 'open' command has been sent. The electrician checks the PLC output module and finds the output LED for that valve is OFF. What is the most likely initial troubleshooting step?
Since the PLC output LED is OFF, the PLC is not commanding the valve to open. The most logical first step is to check the PLC ladder logic to determine why the
Start free practice for Electrician Red Seal
150 questions · no signup required · 40 free questions per day
Question: A production line operator reports that a valve controlled by a PLC output is not opening, even when the HMI indicates the 'open' command has been sent. The electrician checks the PLC output module and finds the output LED for that valve is OFF. What is the most likely initial troubleshooting step?
Answer options:
- Verify the valve's physical power supply and coil continuity. ✅ Check the PLC ladder logic for the valve's control rung.
- Inspect the HMI-to-SCADA communication link.
- Replace the PLC output module immediately.
Correct answer: Check the PLC ladder logic for the valve's control rung.
Explanation: Since the PLC output LED is OFF, the PLC is not commanding the valve to open. The most logical first step is to check the PLC ladder logic to determine why the output is not being energized. If the logic is correct, then issues with the PLC itself (like a faulty output card) or communications to the PLC from the HMI would be investigated.
Start free practice for Electrician Red Seal
150 questions · no signup required · 40 free questions per day
More about Electrician Red Seal
Related Questions
- A residential garage is to be wired with a 15 A, 120 V duplex receptacle. According to the Canadian Electrical
- During a renovation of a commercial kitchen, an electrician needs to replace an old single-phase, 240 V, 5 kW
- A commercial kitchen is being renovated, and several new 4 kW, 208 V, single-phase electric ovens are being in
- What is the minimum working space depth required in front of an electrical panel rated 200 A, 120/240 V, locat
- A Red Seal electrician is setting up temporary power for a construction site. The main temporary service is a
- A new industrial facility requires a 600 V, three-phase, 150 A feeder to supply a motor control centre. The co
More for Electrician Red Seal candidates
Practice tests
Question explanations
- A residential garage is to be wired with a 15 A, 120 V duplex receptacle. According to the Canadian Electrical
- During a renovation of a commercial kitchen, an electrician needs to replace an old single-phase, 240 V, 5 kW
- A commercial kitchen is being renovated, and several new 4 kW, 208 V, single-phase electric ovens are being in
- What is the minimum working space depth required in front of an electrical panel rated 200 A, 120/240 V, locat
Ready to practice?
Free, no signup required. Build a wrong-question list as you go.
Start Free Electrician Red Seal Practice →Related courses
Other Canadian certifications candidates often prepare for alongside this one.