Allen-Bradley ProcessLogix 1756-IA16, Справочное руководство, Страница: 55 / 120

Publication 1757-RM810A-EN-P - May 2002
Functional Blocks 3-15
SITEXTARRCH
Description Provides a read/write interface to a Text (or String) array of data from a serial device.
Function
•
Reads data from the connected block and writes data to the associated field device. Or, reads data from the
associated field device and makes it available to the connected block.
•
Supports up to 8 Text values (STR [1..8]) from the device. Since the maximum size of the interface to the device is
64 bytes, the valid range of values depends on the combination of number of string values (NSTRING) and length
of string values (STRLEN) as follows.
•
If NSTRING is 1 and STRLEN is 64, valid STR [1..8] range is 1.
•
If NSTRING is 2 and STRLEN is 32, valid STR [1..8] range is 1 to 2.
•
If NSTRING is 4 and STRLEN is 16, valid STR [1..8] range is 1 to 4.
•
If NSTRING is 8 and STRLEN is 8, valid STR [1..8] range is 1 to 8.
•
Provides access to the array of data by other blocks – one element at a time.
•
Sets an overall error flag (ERRFL) ON when the array data is invalid and generates a detailed error code
(ERRORCODE).
•
Provides bad PV flag (BADPVFL) and initialization request flag (INITREQ) parameters to mirror the status of the
ERRFL parameter – data is valid or invalid.
Inputs Up to 8 string values depending on whether the length of the string is 8, 16, 32, or 64 characters.
Outputs See above.
Associated
Block Prior to loading, block must be “associated” with 1 channel of corresponding SIM block that interfaces with physical
FTA A and FTA B hardware at execution runtime. Use channels 0-15 for FTA A and channels 16-31 for FTA B. For
optimum performance, assign channels to SIM block for given FTA contiguously. For example, if you have four
SITEXTARRCH blocks to use with the FTA A, assign them to SIM block channels 0, 1, 2, and 3 rather than 0, 2, 4, and
6.
Parameters ACCLOCK
AUXDATA [0..7]
BADCODE
BADPVFL
DEBUG
DEVADDR
ERRCODE ERRFL
EXECCOUNT
FETCHMODE
FREEZETIME
INITREQ
IOCNUMBER IOCSTATE
IOCTYPE
IOMCONN
NSTRING
ORDERINCM
STARTINDEX STR [1..8]
STRLEN
UPDATOPT
WRITEOPT
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