Chapter 3 Example Applications
FieldPoint FP-3000 User Manual 3-12
©
National Instruments Corporation
In the case of Analog Output blocks, you do not need to tell the block to use
the scaling parameters. The block will always use both XD_SCALE and
PV_SCALE parameters.
Set Up Scheduling
Before the block will operate, you need to schedule the block to execute.
All Fieldbus function blocks (including function blocks on the FP-3000)
execute according to a schedule. You can specify the order of function
blocks in the schedule and the rate at which the schedule is repeated. To
make the configurator create a schedule for your block, complete the
following steps:
1. Double-click on Function Block Application in the tree view of the
configurator.
2. Drag the block from the tree view to the application view. The
configurator automatically generates a schedule for the block that
causes it to run every second (refer to the documentation that came
with your configurator for information about changing the execution
period).
3. To download this schedule to the device, select Configure»Download
Configuration. A dialog box appears that enables the configuration to
be downloaded. Go through the download process as described in the
documentation that came with your configurator. Since the block is not
scheduled when you start the download, its actual mode does not
change until the download is complete.
Bring the Block Online
1. Go to the MODE_BLK parameter and set the TARGET to Auto.
2. Re-read the MODE_BLK parameter. The ACTUAL field should go to
Auto. If it does not, refer to AppendixC, Fieldbus Parameters, for
more information.
Once the block goes to Auto, it is fully operational. You can adjust the Set
Point by writing a value between 0 and 100 to SP. The current flow through
the heating element will vary.
If you are only interested in making FP-3000 output current and not
interested in closed loop control, you are finished with this example.