OPC90 Server
7.29 Specification Block (SPEC)
The SPEC OPC90 block is used to retrieve block specification data for any
configured Bailey function block. This block is similar to the OPC90 Server block
BLK with the exception that the client does not have to send a command to read
the specifications and cannot browse blocks using a NEXT tag. The SPEC block
retrieves block specification information through background polling activity. The
block address is configured in the RING, NODE, MODULE and BLOCK attributes
of this block in the OPC90 Server configuration and thus cannot be changed by
OPC Clients. Each time the Bailey block data is polled, the specification values
returned are copied to the S01_VALUE through S63_VALUE tags. Specification
text description data is returned in the corresponding S01 to S63 tags.
Restrictions: None, this OPC90 block can be utilized with all Bailey interface
types.
TAGNAME TYPE ACCESS DESCRIPTION
ADDR_RING VT_I2 Config/
Read/Write
Bailey ring address.
ADDR_NODE VT_I2 Config/
Read/Write
Bailey node address.
ADDR_MODULE VT_I2 Config/
Read/Write
Bailey module address.
ADDR_BLOCK VT_I2 Config/
Read/Write
Bailey block address.
MESSAGE VT_BSTR Read Provides the block operational message.
TAG VT_BSTR Read Provides the block name.
TAGLONG VT_BSTR Read Provides the block long OPC path name.
TAGDESC VT_BSTR Read Provides the block descriptor.
QUALITY VT_BOOL Read Current quality of Bailey values (0-good, 1-bad).
ACKNAK VT_I2 Read Result of the last block read. A non-zero code
indicates an error has occurred.
FC VT_I2 Read Function code # returned for the block.
FCNAME VT_BSTR Read Function code name returned for the block.
SX_COUNT VT_I2 Read Number of valid specifications for block.
SPEC_FORMAT VT_I2 Read/Write Determines how specification data is to be
formatted (see note 1).
S01 to S63 VT_BSTR Read Text description data for specifications 1 through
63.
S01_VALUE to
S63_VALUE
VT_R4 Read/Write Value for specifications 1 through 63.
Since Bailey function blocks can have up to 63 specifications, tags exist for the
maximum number of specifications. The actual number of valid specifications for
any given block read can be determined by examining SX_COUNT or the
descriptions assigned to them in tags S01 to S63. Null descriptors indicate the
specification number is not valid for the block read.
Some Bailey specifications can be modified while the block is executing. These
are called tunable specifications and are indicated as such by the specification
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