Sine Systems RFC-1/B Instruction Book

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allowing the RFC-1 to make and receive telephone calls while the power is off. This is often
very important where the controlled site is very remote or difficult to reach.
The RFC-1 may be operated on an uninterruptable power supply of the type designed for
personal computers. An example of this is the Tripp Lite BC250 which is available from Digi-
Key (800-344-4539) for about $129.00. The BC250 will operate the RFC-1 for about 1.5 hours
without external power. The BC250 is not an "instant switching" UPS but this is not required
since the filter capacitor in the RFC-1 is capable of providing power to the RFC-1 during the
switching time.
Alternately, the RFC-1 may be operated during power failures by any means that supplies
+ 15.2 to +19.9 volts DC to the "12 VAC" terminals on the relay panels instead of the normal
12 volts AC. The DC source should be "floating" (neither side connected to ground) to allow
the telemetry section to work properly. Polarity of the voltage is unimportant as this
connection point precedes the bridge rectifier in the the RFC- 1 power supply. The RFC- 1 may
be powered by DC at all times, if desired. The following is a simple circuit that will allow
emergency operation on batteries for a cost of less than $20.00:
DI to D4; 1 N4005 (Radio Shack 276-1104)
D5; 6.2 volt, 1 watt zener (Radio Shack276-561 )
Cl ; 47 pF or 50 pF; 16 to 35 volt electrolytic (Radio Shack 272-1027)
RY1 ; relay, SPDT, 1 2 VDC, 300 to 500 ohm coil (Radio Shack 275-248)
WARNING!
It is very important that this circuit remain
floating, i.e. not connected to ground. This is important because the telemetry
sampling in the RFC- 1 is floating.
The value of Cl should be just large enough to keep RY1 pulled-in during normal power
conditions. If its value is too large, the switchover time will be excessive and the RFC-l's clock
will reset. The value of C 1 shown above is the correct value for the indicated relay.
The 18 volt battery consists of three 6 volt heavy-duty lantern batteries wired in series. These
are available from Radio Shack: stock # 23-016. These batteries will power the RFC-1 for
about 14 hours. If only a very short term back-up is needed, two alkaline 9 volt batteries
may be used. This will operate the RFC-1 for 30 minutes to one hour, depending on use. The
batteries will need to be changed at intervals of 12 to 18 months even if they are seldom used
because of their limited shelf life.
3.00.2
Installation
page 5.8

Sine Systems RFC-1/B Specifications

General

Brand	Sine Systems
Model	RFC-1/B
Category	Remote Control
Language	English