User manual

Publication 1768-UM001C-EN-P - November 2007
Develop Applications 77
Monitoring Controller
Status
The CompactLogix controller uses Get System Value (GSV) and Set System
Value (SSV) instructions to get and set (change) controller data. The controller
stores system data in objects. There is no status file, as in the PLC-5 processor.
The GSV instruction retrieves the specified information and places it in the
destination. The SSV instruction sets the specified attribute with data from the
source.
When you enter a GSV/SSV instruction, the programming software displays
the valid object classes, object names, and attribute names for each instruction.
For the GSV instruction, you can get values for all available attributes. For the
SSV instruction, the software only displays attributes you are permitted to set.
Some object types appear repeatedly, so you may have to specify the object
name. For example, there can be several tasks in your application. Each task
has its own TASK object that you access by the task name.
You can access these object types:
Monitoring Connections
If communication with a device in the I/O configuration of the controller
does not occur for 100 ms or 4 times the RPI, whichever is less, the
communication times out and the controller produces these warnings.
• The I/O status indicator on the front of the controller flashes green.
• A
shows over the I/O configuration folder and the
timed-out device.
• A module fault code is produced, which you can access via:
– the Module Properties dialog.
– a GSV instruction.
• AXIS
• CONTROLLER
• CONTROLLERDEVICE
• CST
• DF1
• FAULTLOG
• MESSAGE
• MODULE
• MOTIONGROUP
• PROGRAM
• ROUTINE
• SERIALPORT
• TASK
• WALLCLOCKTIME
!