EST LSS4 - Page 113

Remote
Annunciator
Power
Calculations
Device
RSA4-CPU
RSA4-COM
SLU-16R
Overview
System
Calculations
TheRS
AHCPU
requiresa 24 VDC
power
source.The
following
areas
mustbe
addressed:
1
. A
minimumof
18.0V
is
requiredatthe
RSA4-CPU.
2.
Minimum
supply›
oltage
available
is
20.4
VDC.
3.The
Standbyand
Alarm
current
requirementsofthe
RSA4-CPUand
the
option
modulesto
which
it
is
connected
mustbe
known.
4.
Maximum
total
available
currentper
power
supply
is 1.5
amps.
Calculations
Apower
consumption/wire
sizin_
calcul
ation
mustbe
performedto
determinethewire
sizeand
wire
lengthfora
•_
iven
load.
Below
is
Table
A-5,
whichmaybe
usedto
determine
RSA4-CPU
loading°.
Quantity
Table
A-5:
RSA4-CPU
Current
Worksheet
Standby
Total
Alarm
(Amps) Standby
Current
Current
(Amps)
(Amps)
0.0176
0.0074
0.001
0.0176
0.022
0.006/LED
FigureA-
1,
below,
show'sthe
RSA4-CPUc
ircuit.
20.4V MAX
f2SA4-CPU
POWEI
FEEDEI?
FigureA-1-
RSA4-CPU
Wiring
Total
Alarm
Current
(Amps)
(WCALC.
CMP)
The
valueof
RMAX
is
determined
using
Ohm'sLawfor
currentv
alues
from
0.25to3.5
amps:
LSS4
Installation,
Operation,and
Maintenance
Manual
A.9