Chapter 4 Installing and Using the FieldPoint Software
FieldPoint FP-1000/1001 User Manual 4-20
©
National Instruments Corporation
3. Select the I/O Items, which you configured in FieldPoint Explorer,
that you want to read or write as a part of this group.
Many OPC clients can use the “Browse Address Space” feature of
the FieldPoint OPC Server to show you a list of all of the I/O Items
you configured in FieldPoint Explorer. However, if the OPC client
you are using does not support this feature, you may need to type
the Item IDs of the I/O Items directly. The naming convention of
the FieldPoint Item IDs is [
Comm resource name
]\[
Device
Name
]\[
I/O Item name
] where the Comm resource, Device, and
I/O Item names are the names given in FieldPoint Explorer. For
example, an Item ID associated with one of the I/O Items shown in
Figure 4-1 would be
FP Res\FP-TC-120 @1\Channel 0.
In most cases, the preceding steps are all that is required to configure an
OPC client to read from I/O items of the FieldPoint OPC server. In some
cases, the OPC client may require more information about the
FieldPoint OPC server. The following list contains additional
information about the FieldPoint OPC server, which you may find
helpful.
• The FieldPoint OPC Server does not require an
Access Path
. Some
OPC clients may expect the access path to be included in the
Item ID name or may request the access path when you select I/O
Items. You should be able to leave the access path blank (empty
string).
• The FieldPoint OPC custom interface is an out of process server.
• The FieldPoint OPC Server supports both synchronous and
asynchronous reads and writes.
• The FieldPoint OPC Server uses the “GetErrorString” method to
return error and diagnostic messages from the FieldPoint server and
hardware. OPC clients that do not support this method may only
give you error messages like “Bad, non-specific” along with an
error code. Some OPC clients that do not support this
“GetErrorString” method may still provide a way for you to
manually look up the FieldPoint message corresponding to the error
code using the method.
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