User`s manual

GFK-2334A Chapter 5 PROFIBUS Master Status and Diagnostics 5-9
5
Get Master Status (2)
The Get Master Status Command provides detailed status information about the Master
CPU366.
Get Master Status Command Block – Basic Example
The following command block accomplishes the following:
Get Master Status.
Return the COMMREQ Status Word to %R10—%R13.
Return the Device Status to %R251—%R259.
Word Dec (Hex) Definition
Word 1 4 (0004) Length of command Data Block
Word 2 0 (0000) Always 0 (no-wait mode request)
Word 3 8 (0008) Memory type of COMMREQ status word (%R)
Word 4 9 (0009) COMMREQ status word address minus 1 (%R10)*
Word 5 0 (0000) Reserved
Word 6 0 (0000) Reserved
Word 7 2 (0002) Get Master Status command number
Word 8 8 (0008) Memory type to write response (%R)
Word 9 250 (00FA) Starting Address to write response (response written to %R251)
Word 10 9 (0009) Maximum size of response area
(Word 7) Command Code: Word 7 specifies the Command code for the COMMREQ to
be executed. Get Master Status = 2
(Word 8) Local PLC - Memory Type: Words 8—9 specify the location in the PLC where
the response will be written. Values for Word 8 are listed on page 5-5.
(Word 9) Local PLC - Memory Starting Address: Word 9 is a 0-based offset that
determines the starting address in the local PLC in which the response is to be written.
The value entered is the offset (0-based) from the beginning of PLC memory for the
memory type and mode specified in Word 8. This offset will be either in bits, bytes, or
words depending on the mode specified (for example, if Word 8=16 and Word 9=2, then
the starting address will be %I17). Valid ranges of values depend on the PLC’s memory
ranges.
(Word 10) Response Memory Size: Words 10 specifies the size of the memory block for
the response. The COMMREQ has built-in future expansion space in the response field.
The Response Memory Size (including the future expansion space) is 9 words. The user
is responsible for assuring that this area is large enough to contain the requested data
without overwriting other application data. It is recommended that the future expansion
space be allocated initially, to avoid problems if future firmware upgrades use 9 words for
the response.