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 respect 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).

X = Normally open contact

I = Normally closed contact

1 = V250LA4 MOV or equal

2 = 1N4004 diode or equal

 

 

 

RELAY

 

 

 

 

RELAY

 

 

K5 (K7)

 

 

 

 

K6 (K8)

 

 

 

 

 

 

 

 

 

x

 

I

 

 

I

 

 

 

 

 

 

x

 

 

x

 

 

 

CLK1 OR CLK2

 

 

 

 

 

 

 

MASTER CLOCK

1

2

3

4

5

6

7

8

FIELD CONNECTIONS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A

10 ASB MAX.

 

 

 

 

 

 

 

1

CLOCKS

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

B

24Vdc

 

2

 

 

 

 

 

 

 

–

 

 

 

 

 

 

 

 

 

Figure B-15

Two-Wire Pulse Alternating (24Vdc)

24A715/24A715M Master Clock Installation Manual

B-17