Fuses protect the ESA system's instrument circuits. If a fuse is found to be blown during troubleshooting, replace it with an Eaton Bussmann KTK-1 fuse or equivalent 1 A, 600 V, fast-acting cartridge-style fuse.
ELECTRICAL DANGER
Before opening the enclosure or touching any internal components, de-energize, lock out, and tag out all power sources to the ESA enclosure. Failure to do so may result in electric shock and death.
To replace a fuse:
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Open the ESA enclosure.
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Locate the fuse holder containing the fuse requiring replacement.
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Lift up on the fuse holder tab to open the fuse holder and expose the fuse.
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Remove the old fuse.
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Install the new fuse into the fuse holder, observing the correct orientation.
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Close the fuse holder until it latches.
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Close and latch the enclosure door.
NOTE:
A fuse should always be installed between the ESA system and the bus PT wiring. This provides selective coordination so that a fault on the ESA instrument circuit clears locally without affecting the plant's operational PT circuit.
Clean the exterior of the enclosure as needed to remove excess buildup of dust, debris, or other contamination.
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Ensure the enclosure door is shut while cleaning to prevent contact with internal components.
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Use a non-conductive, non-residue cleaner (for example, 70% isopropyl alcohol / 30% water mixture) and a soft cloth that will not scratch the enclosure surface.
NOTE:
The guidance below assumes the InsightCM™ device (cRIO) is powered, online, and connected to the InsightCM™ server. If the device itself is unreachable, resolve the communication issue (see Section 10 — Communication Failures) before troubleshooting individual signals.
A missing voltage signal with the device online usually indicates an open circuit on the PT side — most commonly a missing or blown fuse. Confirm that the fuse for the affected phase is present and intact, and replace it if necessary (see Fuse Replacement above). A fuse must be installed between the ESA system and the bus PT to provide selective coordination.
Loss of a current signal points to an open circuit between the CT transducer and the cRIO input. To locate the break:
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Place a voltmeter across the positive and negative leads close to the CT and measure the AC voltage. A healthy transducer under load will show a small AC signal.
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If a signal is present at the CT, continue measuring along the cable run back toward the cRIO to find the point where the signal is lost.
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Repair the open connection at the identified location.
Incorrect phasor readings are typically caused by a current transducer that is either reversed in polarity or clamped onto the wrong phase. Use the phasor diagram to diagnose:
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If a current phasor sits approximately 180° from where it should be, the transducer polarity is reversed. Enable the Reverse Polarity setting for that sensor in the asset configuration and push the updated configuration to the device.
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If the current phasors are simply in the wrong order, reorder the current phase assignments in the InsightCM™ asset configuration so that each CT is associated with the correct phase.
Loss of communication with the cRIO device is most often caused by poor Ethernet termination or by port blocking or firewall rules. Troubleshoot in the following order:
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Verify the physical link using an Ethernet cable tester to confirm the cable run from the cRIO to its endpoint is intact.
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Confirm the network configuration of the cRIO — IP address and subnet — matches the network it is connecting to.
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If cabling and network settings are both confirmed correct, contact the facility's IT group to verify that no firewall or port blocking is preventing the cRIO from communicating with the InsightCM™ server.