Rockwell-automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE Instrukcja Użytkownika Pobierz pdf (Strona 50)

Creating Command and Status Blocks

Chapter 4

4-14

The SPI module receives status from the target device and returns Custom

Data Status (CDS) to the PLC processor whenever the target device:

receives the Custom Data Block (CDB) from the SPI module

is polled by the SPI module

The contents of the CDS are different for each condition:

For this origin: CDS contains

CDB command the reflected commandcode pairs that you entered in CCB

polling numeric values (status bits and process variables)

specified by the commandcode pairs and located in their addresses

The size is the same for both conditions and is equal to the sum of:

four header words

number of command-code pairs for status that you entered in CCB

If the SPI module detects a fault, it returns the CDS with only the first

three words containing fault diagnostics:

words 1 and 2 identify the target device having the fault

word 3 contains the 70xy series error codes described in chapter 6.

We identify fault diagnostic information in bold print.

CDS Bit/Word Map

Word 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 0 CR CE 0 DC Device ID

2 Zone Address (if used) Device Address

3 If the SPI module detects a fault, it sets an error code (70xy series) to help identify the cause of the fault

4 0 0 0 0

starting at 5,

up to 64

If no communication fault:

If origin is a CDB, CDS reflects all the commandcode pairs that you entered in CCB.

If origin is polling, CDS returns numeric values specified by the commandcode pairs.

If SPI detects a communication fault, it

clears all status words starting at word 4, and returns words 13 with a diagnostic code (70xy) in word 3.

Custom Data Status, CDS, to

Return Device Status From

the SPI Module

1 2 ... 45 46 47 48 49 50 51 52 53 54 55 ... 61 62

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Rockwell-automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE Instrukcja Użytkownika Strona 50