
3Ć48 Theory of Operation: Upload/Download
Original Ć June 1990CE4.2:CL6211
3.4 Upload/Download
When the controller is first powered up it does not contain the
information it needs to perform control. The user defined control
information that must be provided to the controller is referred to as
configuration" data. The transfer of the configuration data from the
configuring device to the controller is called downloading." The
controller only supports total downloads. A total download always clears
the old configuration and re-configures the controller.
The process of moving data from the controller back to the configuration
device, is called uploading." This allows updating of the configuration
information after tuning changes have been made at the controller. Note
that only tuning parameters are uploaded.
3.4.1 Initiating a Download
If the controller is currently configured and operating when a download is
initiated, the Function Sequence Table (FST) is allowed to complete
execution before the download starts. The controller holds its analog
and discrete outputs at the values they were at prior to the download. It
then goes into the database hold state which indicates the database is
now invalid.
3.4.2 Completing a Download
During the download control action is suspended and the controller
indicates its database hold condition. Once the download is completed,
the restart parameters are set to their proper values and the controller
comes out of the database hold state. See section NO TAG on page
NO TAG for a more detailed explanation of restart parameters after a
download. The controller then updates its non-volatile memory (NVM)
with the new configuration data.
If an error occurs while downloading a simplex controller and the
download is not accepted, the controller will remain in the database hold
state. The controller will come out of the database hold state when either
a download is successful or the controller is power cycled. Power
cycling causes the controller to reload its previous configuration from
NVM.
Comentarios a estos manuales