Using the Logic Editor
372 SPU 780 01EMAN May 2002 149
Sweep (Online Only)Overview The Sweep function is a powerful diagnostic tool that lets you solve logic for a set
number of scans or solve logic continuously with a constant time between scans.
Constant Sweep
Mode The Constant Sweep mode sets the controller to scan and solve lo gic a nd upd ate I/
O continuously, but with a constant time interval between scans.
If the actual scan time is less than the imposed scan time, the controller waits for the
imposed scan time to elapse before performing the next scan. If t he actual scan t ime
is more than the imposed scan time, the controller finishes the scan, the n contin ues
on with the next scan. This lets you slow the scan time to when debugging lo gic, s o
that the controller doesn’t solve logic too quickly for you to catch errors.
Performing a
Constant Sweep From the networks panel (tree), right click menu:
Single Sweep Single Sweep mode sets the controller to scan and solve logic, and update I/O for a
set number of scans only. When the sweep is finished, the controller stops solving
logic and updating I/O, waits until you manually trigger the sweep.
Step Action
1 Select Sweep.
2 In the Sweep Mode area, select the Constant Sweep radio button.
3 Enter the target time (in 10’s of milliseconds) for each scan in the Time box.
4 Enter a 4xxxx register to hold the target time value in the Register (4xxxx) box.
The actual time taken for each scan is placed in the next register, so a total of
two registers are used.
5 Click OK.
WARNING
Ensure hardware not part of critical process.
The Single Sweep function should not be used to debug controls on
machine tools, processes, or material handling systems when the y are
active. Once the set number of scans is solved, all outputs a re frozen in
their last state. Since no logic solving is occurring, all input informati on
is ignored. This can result in unsafe, hazardous, and destructive
operation of the machine or process connected to the controller.
Failure to follow this precaution can result in severe injury or
equipment damage.