Force
Use Force to override an I/O module's values in the controller. This value can be:
- A structure member of an I/O tag
Since an I/O tag is a structured tag, the force is applied to its structure members (of type BOOL, SINT, DINT, INT, or REAL). Only one restriction applies to which members can be forced (for example, cannot force configuration data).
- An alias to an I/O structure member (of type BOOL, SINT, INT, DINT, or REAL)
Forcing an input value overrides the actual input value being received from the controller, but does not affect the value received by other controllers monitoring that physical input module. Forcing the input value overrides the value no matter what the state of the physical input is.
Forcing an output value overrides the logic for the physical output module. Other controllers monitoring that output module in a listen-only capacity also monitor the forced value.
If the data value is of type SINT, INT, or DINT, then force either the whole word or an individual bit(s) within the word. From the Data Monitor, select individual bits either by clicking on the + sign next to the
Tag Name
field, or by choosing the bit from the Force Mask's drop-down palette. The status of individual bits is:- No force
- Force on
- Force off
If the data value type is REAL, then individual bit forcing is not supported. BOOL data types can only be forced at bit level.
Since an alias tag shares the same data value with the base tag, forcing an alias tag causes the base tag to be forced also. Removing a force from an alias tag removes forcing from the data value to which the alias tag refers, and any aliases to that value become unforced. If the alias tag points to a bit in a base tag, any forcing on that bit is removed.
Using the Data Monitor or the Ladder Editor, manipulate I/O forces on individual tag elements. From either of these:
- Force a tag element on or off (for tags of BOOL type only)
- Remove the force from a tag element
To manipulate all I/O forces in the controller, use the Online bar or the Forcing command from the Logic menu. Once any tag element is forced, the Online bar force status indicates that forces exist in the controller, as well as whether forces are enabled or disabled. From this bar, remove, enable, or disable all forces in the controller.
To determine which tags are forceable , choose
Forceable Tags
from the Data Monitor Show
filter.
TIP:
- Force buffers are only applied to produced tag data as the data is being sent out in the forced image.
- Only enable and/or disable forces at the controller level; cannot enable/disable forces only for a particular module, tag collection, or tag element.
Provide Feedback