What is a monitored CCR (L-829)?
A constant current regulator with a built-in monitor — it holds the loop current, checks it, and reports status and alarms to the control system.
L-829 is the FAA designation for a constant current regulator with monitoring. It does what an L-828 regulator does, holding the series-circuit current at the selected step, and a built-in monitor also checks the output and reports status and alarms to the control system, such as the ALCMS. A separate L-827 regulator monitor provides the monitoring function as its own unit.
Monitoring gives early warning: a loss of output or a current outside the expected range is flagged to the control room instead of waiting for an inspection or a pilot report. It does not repair anything or replace the CCR’s own protection, and a monitor that is ignored, drifting or cut off gives a false sense of security. Which conditions are monitored beyond the output current depends on the design and the manufacturer.
- Regulate. The regulator holds the series-circuit current at the selected step, as any CCR does.
- Sense. A current sensor reads the output current.
- Monitor. The built-in monitor checks that the current and the unit’s condition are as expected.
- Report. Status and alarms go to the ALCMS or control panel by contacts or a data link.
- Confirm. A person confirms the alarm and finds the cause on site if needed.
- Test & record. Test the alarm path as well as the output, and log the results.
Frequently Asked Questions
Q1What is a monitored CCR (L-829)?
L-829 is the FAA designation for a constant current regulator with monitoring. It does the same job as any CCR, holding the series-circuit current at the selected step, and also has a monitor built in that checks the output and reports the unit's status and alarms to the control system.
Q2What is the difference between L-827, L-828 and L-829?
In FAA AC 150/5345-10, L-828 is a regulator without monitoring, L-829 is a regulator with monitoring, and L-827 is a regulator monitor, a separate unit that provides the monitoring function. Check the specification version for your project.
Q3What does the monitor check?
At least the output current, so a loss of output or a current outside the expected range can be flagged. Many units also report on/off state, the selected step and other conditions such as open circuit, overcurrent or temperature. Exact functions and options vary by manufacturer.
Q4Where do the status and alarms go?
To the control system, such as the ALCMS or a control panel, through relay contacts or a serial or network link, so the operator or maintenance team is told about a fault without waiting for an inspection or a pilot report.
Q5Does the monitor fix a fault?
No. It reports; it does not repair or replace the regulation and protection in the CCR. A person still has to confirm the alarm, find the cause and make the circuit safe.
Q6What goes wrong with monitoring?
Alarms that are ignored or acknowledged without action, a drifting current sensor, a broken communication link that hides the real state, and settings that no longer match the circuit. Test the alarm path regularly, not just the CCR output.
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