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TYPE 13—Two-Wire Pulse Alternating (24Vdc)
Every minute from 59 seconds to 00 seconds, a 24Vdc signal is applied on lines A and B,
causing the clocks to advance one minute. The polarity of the pulse is alternated each
minute to cause A to be positive with respect to B one minute, then B positive with re
-
spect to A the next minute, and so on.
During power interruptions, the master clock accumulates the number of minutes lost.
When power is restored, the master clock sends 30 pulses per minute to correct the
clocks. The clocks can be manually advanced 60 minutes using the master clock. A total
of 62 pulses are issued during manual advance (two normal pulses plus 60 extra advance
pulses).
24A715/24A715M Master Clock Installation Manual
B-17
12345678
CLK1 OR CLK2
x
x
x
x
RELAY
K6 (K8)
RELAY
K5 (K7)
II
MASTER CLOCK
FIELD CONNECTIONS
X = Normally open contact
I = Normally closed contact
–
10 ASB MAX.
+
A
B
1
= V250LA4 MOV or equal
1
2
= 1N4004 diode or equal
2
24Vdc
CLOCKS
Figure B-15
Two-Wire Pulse Alternating (24Vdc)