CTI 2572-A, Installation And Operation Manual

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CTI 2572-A Installation and Operation Guide
30
Ladder Logic Example
The following diagram illustrates the ladder logic that executes the Start Network Server command
block. This example assumes that the command block is located in V memory starting at V500 and
that command slot 1 is used for the command.
Rung 1 loads the location of the Command Block (V500) into Command Slot 1 (WY5). Once the
control relay is on, it seals off the command. The load command will be bypassed on subsequent
scans.
Rung 2 sets the C
OMMAND
T
RIGGER
(WY4.3) and C
OMMAND
M
ODE
(WY4.2) when the N
ET
C
FG
bit
(WX1.3) is on and the C
OMMAND
B
USY
bit (WX2.3) is off. When the logic sees the 2572-A raise
C
OMMAND
B
USY
(WX2.3), it lowers the C
OMMAND
M
ODE
(WX4.2) and C
OMMAND
T
RIGGER
(WX4.3), completing the coupled mode cycle.
The N
ET
C
FG
bit will be raised by the 2572-A at any time the network configuration parameters are
not set. Therefore this logic will re-execute the Start Network Server command, if the 2572-A is reset
for any reason.
NOTE:
Do not use retentive relays in this logic. Proper operation of this logic depends on the control relay
transitioning from off to on when power is cycled.
LDC
WY5
500
C100
C100
C100
WY4.2 WX2.3
WY4.3
WX1.3
WY4.3
Set the command to
Coupled Mode
Sets the Command
Trigger