Physical Description
6
Static RAM
The software design and memory organization supports the complete download of all
software, including revised LAN drivers that are invoked after completion of the down-
load. The downloaded software is held in static RAM. The software can be downloaded
while the I/SITE LAN is on-line with I/NET.
The content of static RAM is retained in the event of a power outage, as long as the
backup battery has power (i.e., up to 300 hours). When the battery power has depleted,
the content of static RAM is cleared (refer to “Battery Backup”, below).
EPROM
Erasable/programmable ROM (EPROM) stores the controller firmware, as well as a
firmware download handler and boot record firmware.
Battery Backup
The 7798 I/SITE LAN provides battery-backup of static RAM contents and of the
clock/calendar. The onboard NiCad rechargeable battery provides backup for up to 300
hours during a power failure.
Note:
The backup battery must be fully charged in order to provide the full span of backup power.
Due to normal discharge during product storage and shipment, the battery may not be fully
charged immediately following installation and power-up. You must allow the controller to
operate continuously for a minimum of seven days (168 hours) before depending on battery
backup.
Power Supply
Electrical power for the I/SITE LAN enters at the bottom-left edge of the board (TB1). A
single 24 VAC 50/60 Hz, 40 VA Class II external transformer provides input power for
the I/SITE LAN.
ViewCon
The ViewCon consists of an LCD and keypad (see
). The LCD is a 64
×
240 pixel
graphic display mounted behind the plastic cover. For the 7798 I/SITE LAN, the LCD
displays four text lines with up to 40 characters per line. The keypad is comprised of a
polyester membrane key panel that is mounted to the front panel of the plastic enclosure.
The keypad provides eight function keys identified as F1 through F8. The actual opera-
tion of the function keys varies dynamically based on the key function indication shown
on the LCD next to each respective key.
Refer to
for more information about ViewCon operation.
