Sensaphone SCADA 3000 Users manual - Manual (Page 43)

4-3
Chapter 4: Power Supply
Compute the Total Power by multiplying the Total Current by the Supply Voltage
TOTAL POWER (watts) = 15V x Total Current =
_____________(Watts)
•This Watt rating is the average power that the system will consume during normal
operation; however, during startup the power is significantly greater.
*The 24V supply on the CPU and modules may be used to power 4-20mA trans-
ducers; be sure to account for these in your calculation by entering the number of
transducers connected.
A sample computation follows:
Main RTU power*
00.215 Amps
Modem option 1 x 0.085 Amps = 00.085
Real Voice option 1 x 0.008 Amps = 00.008
Universal input module* 2 x 0.100 Amps = 00.200
Relay output module 1 x 0.080 Amps = 00.080
Battery Charge Current 1 x 0.600 Amps = 00.600
Powered 4-20mA transducers 3 x 0.038 Amps = 00.114
Total Current 1.302 Amps
Warning: The Total Current must not exceed 3.5 Amps.*
Total Power (Watts) = 15 x 1.302 Amps = 19.53 Watts
* Exceeding this value will bring the system very close to the rated current of the
fuse (4A). A small amount of margin is required to insure that the fuse doesn’t
blow under normal operation.
Power Supply Selection
To size the power supply properly, multiply the Total Power computed above by 1.5. This will
insure that the power supply will have enough reserve power to operate properly during peak
power demand.
Example: If the Total Power was 19.53 Watts, then the Power Supply should be rated at:
19.53 Watts x 1.5 = 29.30 Watts, or 30 Watts.
Sensaphone SCADA 3000 Power Supplies:
FGD-3100 Hard-wired power supply: 60 Watts
FGD-3110 Plug-in power supply: 50 Watts
(others are available)
BACKUP BATTeRY (optional)
In the event of a power failure, SCADA 3000 can continue to operate if connected to a sealed
lead-acid gel-cell rechargeable battery. The capacity or Amp-Hour (AH) rating of the battery
may vary between 5 and 18 AH.
To compute the appropriate size battery, multiply the backup time required by the Total
Current.
Example: Battery Capacity
= Hours of backup x Total Current
= 12 hours x 1.302 Amps = 15.62 AH