What is a CCR regulator monitor (L-827)?
A separate unit that watches a constant current regulator — it reads the loop current, checks it, and reports status and alarms to the control system.
L-827 is the FAA designation for a regulator monitor: a separate unit that watches the output of a constant current regulator and reports its status and alarms to the control system, such as the ALCMS. It is used with a regulator that has no monitor of its own, such as an L-828. An L-829 regulator does the same job with the monitor built into the same unit.
The monitor watches and reports. It does not hold the current, and it does not replace the regulator’s own protection. Its value is early warning: a loss of output or a current outside the expected range reaches the control room instead of waiting for an inspection or a pilot report. Because it is a separate unit, it is one more item to install, wire, test and maintain, and a sensor on the wrong circuit, drifting limits or an ignored alarm gives a false sense of security. Which conditions are monitored beyond the output current depends on the specification edition and the manufacturer.
- Regulate. The regulator holds the series-circuit current at the selected step. The monitor does not change that.
- Sense. A current sensor on the regulator output reads the loop current.
- Compare. The L-827 checks the reading against its limits.
- Report. Status and alarms go to the ALCMS or control panel by contacts or a data link.
- Confirm. A person acknowledges the alarm and finds the cause, using the regulator’s own indications on site.
- Test & record. Test the sensor, the limits and the alarm path as well as the output, and log the results.
Frequently Asked Questions
Q1What is a CCR regulator monitor (L-827)?
L-827 is the FAA designation for a regulator monitor: a separate unit that monitors the output of a constant current regulator and reports its status and alarms to the control system, such as the ALCMS. It is used with a regulator that has no monitor of its own.
Q2What is the difference between L-827 and L-829?
In FAA AC 150/5345-10, L-829 is a regulator with the monitor built into the same unit, while L-827 is the monitor as a separate unit. L-828 is a regulator without monitoring. The monitoring job is the same, but a separate L-827 is one more item to install, wire, test and maintain. Check the specification version for your project.
Q3What does a regulator monitor check?
At a minimum it reads the regulator's output current and compares it with its limits, then reports the result as status and alarms. Which other conditions it watches, and the alarm limits, depend on the specification edition and the manufacturer, so check the equipment data.
Q4Does the monitor protect or control the circuit?
No. The monitor watches and reports. The regulator holds the current and its own protection handles open-circuit and overcurrent conditions. A monitor gives early warning to the control room, but a person still has to act on the alarm.
Q5What goes wrong with a separate monitor?
The current sensor may be on the wrong circuit or drift out of calibration, limits may no longer match the circuit, the link to the ALCMS may fail and hide the real state, and alarms may be acknowledged without action. Test the sensor, the limits and the alarm path, not just the regulator output.
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