The Model HM-503 Quad Isolated Serial Interface provides four
data lines, electrically isolated from the console. Isolated serial data lines
are required when data lines go to a building, or building section, on a
separate utility power feed. The isolation eliminates problems associated with
ground currents during lightning storms and protects the console from electrical
transients.
The four data lines from the same
HM-503 must go to the same
building. Each data line has the same capacity as standard Sentry serial
interfaces, supporting up to 52 Host Panels, 8 Utility Panels, and one power
supply.
Estimate the requirement of one
HM-503 for every group of up
to 200 apartment panels.
The console can consist of both non-isolated and isolated
interfaces.
The HM-503 is powered by an isolated supply located at the
console. One model HM-532 power supply is included for each HM-503 Interface.
One HM-503 Interface consists of two modules, the computer
interface card and the terminal board. The HM-503 card installs in the Master
Controller computer. It connects to the HM-803 Isolated Interface Terminal Board
with a ribbon cable. The HM-803 attaches to the HM-595 Plastic Track for mounting. The
Interface includes a 6 ft. ribbon cable, Sentry 811-243-01.
Sentry recommends using a 2 pair, 18 AWG cable, (WPW 440),
when connecting between two data lines on the HM-503 Interface, and a remote
terminal board.
