Technical Reference Manual - InduSoft

Communication with Other Devices
Tip: By default, the project will scan the communication worksheet every 600 milliseconds, which is
the rate at which the system tag BlinkSlow toggles. To adjust the rate, manually edit the project file
(i.e., projectname.APP) to add the following entry:
[Options]
MainDrvAlwaysTrigger=tagname
tagname can be either another system tag (e.g., BlinkFast, Second, Minute) or a tag that you have
created. Whenever the value of the tag changes, the worksheet will be scanned and the tags will be
read.
Standard Driver Sheets
In addition to the unique MAIN DRIVER SHEET that is available for each driver, you can create several
STANDARD DRIVER SHEETS for each driver. The STANDARD DRIVER SHEETS provide additional fields,
which you can use to control communication.
To open a STANDARD DRIVER SHEET, right-click on a driver subfolder and select Insert from the resulting
popup (see the following figure).
Sample STANDARD DRIVER SHEET
The STANDARD DRIVER SHEET dialog is divided into two areas:
• Header area (top section), contains parameters that affect the all tags configured in the Body area of this
worksheet
• Body area (bottom section), where you define the relationship between tags in the project and their field
equipment address.
Use the Header area parameters as follows:
• Description field: Type a description of the STANDARD DRIVER SHEET for documentation purposes.
• Increase Priority checkbox: Click (check) to keep the reading and writing commands for this sheet on the top
of the communication queue whenever they are triggered.
Caution: You must give special attention to this worksheet when you enable the Increase Priority
option. If the worksheet keeps triggering communication commands, the project may never be
able to execute the other driver sheets.
• Read Trigger field: Type a tag that triggers the project to read the worksheet automatically when you change
this tag's value.
• Enable Read when Idle field: Type a tag or constant value. Use a tag (or constant) value greater than zero, to
enable reading from the equipment.
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