Rockwell Automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE - Manual (Page 48)

Creating Command and Status Blocks
Chapter 4
4-12
Use this SYS bit/word map to identify:
data layout of the SYS
location of the diagnostic word to describe detected MCC errors
location of invalid device ID and/or device address
number of bits in word 5 to indicate “device OK” on link (in last row)
We identify fault diagnostic information in bold print.
SYS Bit/Word Map
Word | Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 PU
[ 1 ]
Baud Select
[ 2 ]
AI
[ 2 ]
NF
[ 2 ]
DF
[ 2 ]
SYS Block ID
[ 2 ]
2 Device ID (returned for an invalid entry in MCC polling list) Page Number Total Pages
3 Diagnostic Word (Returned for an invalid MCC. See 9000 series error codes in chapter 6.)
4 Zone Address for temperature control devices, only
(Returned for an invalid entry in MCC polling list.)
Device Address
(Returned for an invalid entry in MCC polling list.)
Communication Status Bits (OK Bits) for Devices on the SPI Network
5 Devices 32Ć47 indicated by word 5, bits 00Ć15 (1 bit per device)
6 Devices 48Ć63 indicated by word 6, bits 00Ć15 (1 bit per device)
: : :
18 Devices 240Ć255 indicated by word 18, bits 00Ć15 (1 bit per device)
[ 1 ] Power Up bit 0 = no MCC, or invalid MCC [ 2 ] Mirrors the same MCC bit
1 = SPI module stored a valid MCC
Important: The SPI module returns the SYS after your program downloads
the MCC. For diagnostic data returned in SYS word 3, refer to chapter 6,
Troubleshooting. The return of SYS after each polling sequence is optional.
System Status Block, SYS