Simplex 4100ES — Earth Fault Search

The panel shows Earth Fault Search while the Earth Fault Search diagnostic function is running. Once the search has been initiated, the front panel display tracks how far the search has progressed (10%, 25%… 75%) and then shows the outcome: it either names the offending circuit or reports that the earth fault could not be found. The same message appears on the IDNet card while that card is searching for earth faults on the IDNet line. On the SPS, the circuits searched are IDNet, NAC, and aux power.

Earth Fault Search is a diagnostic that sweeps the external field wiring to help locate circuits with earth faults — an earth fault is a circuit shorted to ground. Most circuits keep operating with a single earth fault, but several at once can disable communications, so they must be located and repaired. The search is conducted by the panel (the FIP) and can be started from the front panel interface or through the Computer Port Protocol (CPP) via a service port. Two search types are supported: a Location Search, which tests all circuits at a location such as the main panel or a transponder, and an IDNet Channel Search, which selectively enables channel isolators and repeaters to determine which segment of the channel wiring has the fault. While the message is up, system alarm and fault processing is suspended, and the fire panel cannot provide fire protection during an Earth Fault Search. When the message comes from the IDNet card, the card is searching the IDNet line and cannot show any alarms or other statuses.

• The Earth Fault Search diagnostic function was initiated — the fault tables give this as the cause; the search may be started from the front panel interface or, through CPP, via a service port.
• An earth fault search is active on the IDNet line: the IDNet card is searching the line for earth faults.

1. Confirm the Detect Earth Fault jumper is installed at each SPS — without it, no earth fault detection can occur.
2. Confirm that only one power supply per location is configured to detect earth faults.
3. Check that IDNet channel isolator addresses are set to the lowest IDNet device addresses, increasing with communication distance from the IDNet card; this makes the search more reliable.
4. If the earth fault is suspected on the IDNet channel and the channel has multiple isolators, run an IDNet Channel Search before a Location Search — a Location Search done first may not yield the correct location, because the IDNet channel takes an extended time to initialize during a Location Search.
5. Log in at the access level required to run diagnostics (above level 1 if necessary).
6. Open the Main Menu, select the Service/Diagnostics menu, then select Earth Fault Search.
7. Choose the search type — Location Search or IDNet Channel Search. For a Location Search, scroll to the card you suspect and press Enter when it is shown.
8. When prompted, choose whether to exclude the AUXPWR (auxiliary power) circuits, then start the search. The panel turns on the earth fault search trouble pseudo-point and a keypad inactivity utility pseudo-point to disable timeout during the search.
9. Repair the earth fault on the circuit named in the result. The search finds only one fault at a time, so if a further fault exists, run the diagnostics again after the first is cleared — faults appear one by one until each has been found and corrected.
10. If the result reads FAULT NOT FOUND (Location Search) or FAULT CLEAR FAIL (IDNet Channel Search), the search acknowledges that a fault exists but could not locate it. The manual's possibilities are: internal wiring earth(s) in the system; hardware or software defects such as a failed isolation circuit; an intermittent earth that occurs inconsistently; a service-port cable grounded through the remote PC's 3-prong plug (a non-grounded plug adapter on the remote PC removes this earth); or a fault on an auxiliary output that was excluded from the search. In some of these cases the problem has to be found manually.

• A Location Search may exclude the AUXPWR circuits, so that modules connected to the 24 V auxiliary outputs can remain in operation during the search; the exclusion option does not apply to IDNet devices, because the entire IDNet communication channel is isolated during each search.
• The power supply that detects earth faults at a location is designated via a jumper setting on the power supply slave.
• While the search runs, all related troubles are suppressed and a single trouble pseudo-point, P438, is activated.
• Earth Fault Search is supported only by new 4100ES modules; 4100 Legacy (slot format) modules are not supported, except for MAPNET channel isolation during a location search.
• The 4009 IDNet NAC Extender has a common ground fault trouble that reports to the panel without the Earth Fault Search being run.

No separate reset is needed — the message clears when the search finishes. At completion, all slaves are restarted automatically, the panel turns off the earth fault search trouble pseudo-point, normal panel operation resumes, and the specific fault information is displayed. The panel returns only one search result at a time. Once the earth fault has been corrected, the manual recommends restarting the system (warm- or cold-start); a further fault can then be found only by running the diagnostics again after the first fault is cleared.