CTI 2572-B / 2500C-2572-B Installation and Operation Manual 35
Ladder Logic Example
The following diagram illustrates the ladder logic that executes the Start Network Services 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.
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
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 TRIGGER (WY4.3) and COMMAND MODE (WY4.2) when the NET CFG bit (WX1.3) is on and
the COMMAND BUSY bit (WX2.3) is off. When the logic sees the 2572-B raise COMMAND BUSY (WX2.3), it lowers
the COMMAND MODE (WY4.2) and COMMAND TRIGGER (WY4.3), completing the coupled mode cycle.
The NET CFG bit will be raised by the 2572-B at any time the network configuration parameters are not set.
Therefore this logic will re-execute the Start Network Services command if the 2572-B is restarted 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.
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