In addition to the guidelines in Table 14, observe these guidelines when wiring the SA/FC Buses and
supply power:
• Run all low-voltage wiring and cables separate from high-voltage wiring.
• Use twisted, insulated, stranded copper wire for all FC and SA Bus cables, regardless of wire size.
• Shielded cable is strongly recommended for all FC and SA Bus cables.
• Refer to the
MS/TP Communications Bus Technical Bulletin (LIT-12011034)
for detailed information
regarding wire size and cable length requirements for the FC and SA buses.
Setup and adjustments
Data protection battery
The battery is pre-installed and connected in the network engine when shipped. Do not disconnect
the battery for any reason other than to replace a defective battery.
Important:
If you are installing a new battery for the first time or you are replacing the
battery, disconnect the power from the NCE25 prior to inserting a new battery.
The 24 VAC supply power to the network engine charges the data protection battery. At initial
startup, the battery may require a charging period of at least 4 hours before it supports data
protection if power fails. Maximum protection (up to 3 consecutive power failures without
recharging time) requires a 15-hour charging period.
With the 24 VAC supply power, the battery slowly loses charge. If the battery completely loses
charge, the network engine real-time clock stops.
Whenever a network engine is disconnected from 24 VAC power for over 30 days, ensure that the
real-time clock is set properly and that the network engine and there is enough power to recharge
the data protection battery.
Powering on the network engine
After applying 24 VAC power, the network engine requires approximately five minutes to become
operational. See
LED Test Sequence at Startup
.
Startup is complete and the network engine is operational when the green RUN LED is On steady
and the red FAULT LED is Off (Figure 16).
Important:
Wait for the network engine to complete the start-up sequence and the RUN LED
to go On steady before initiating any other action on the network engine.
Disconnecting power from the network engine
When 24 VAC supply power to a network engine is disconnected or lost, the network engine
is nonoperational, but the POWER LED (Figure 16) remains on and the data protection battery
continues to power the network engine for several (approximately one to eight) minutes while
volatile data is backed up in nonvolatile memory. The RUN LED goes off when data backup and
shutdown is complete.
Important:
You must install and charge the data protection battery before disconnecting the
24 VAC supply power.
Setting the end-of-line switch
RS485 serial protocol bus segments require proper EOL termination to reduce interference from
signal bounce back on the bus segment.
FC Bus MS/TP applications require a terminated device at each end of each FC Bus segment. See
the
MS/TP FC Bus rules
section for more information on EOL requirements on an FC Bus.
NCE25 Installation Instructions
28