Module configuration command block (mcc), Chapter 3 – Rockwell Automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE User Manual
Page 24
Defining Command and Status Blocks
Chapter 3
3-2
Your ladder logic must send (BTW) a valid MCC to the SPI module after
power-up to prepare it for operation. This can be an MCC header (4 words)
or a complete MCC block (up to 64 words). Only after the SPI module
receives it, can the module operate as follows:
accept any valid command block sent to it by BTW
poll devices on the SPI network
return device-specific status blocks by BTR
return optional system status (SYS) by BTR
Until it receives a valid MCC block, the SPI module can only return the
system status (SYS) block in response to a BTR request.
Important: Your ladder program must always initiate communication with
the SPI module at power-up with the MCC.
Table 3.A
Bit/Word Map of the Module Configuration Command Block (MCC)
Word
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
1
CNE
Baud Select
CNS
NF
DF
MCC Block ID
2
0
0
Page Number
Total Pages
3 and 4
0
0
0
0
The following word pairs (5&6, 7&8, etc.) define SPI network devices.
Important: List them in the order in which you want them polled (queue order).
5
DS
CS
PM
Reserved
Device ID (for first queued BTR)
6
Zone Address (for temperature control devices, only)
Device Address
7
DS
CS
PM
Reserved
Device ID (for 2nd queued BTR)
8
Zone Address (for temperature control devices, only)
Device Address
⇓
⇓
⇓
⇓
63
DS
CS
PM
Reserved
Device ID (for 30th queued BTR)
64
Zone Address (for temperature control devices, only)
Device Address
[ 1 ]
DS
CS
PM
Reserved
SYS Block ID
Reserved
SPI Module Address
[ 1 ]:
You must add the SYS Block ID (11111111) to the list of device IDs if you want the SPI module to return system status.
If so, add it last in the list.
Module Configuration
Command Block (MCC)