MSA ProtoCessor FPC-ED2 - Message Structure; Binary Packed Messages; Payload Contents

7.2.3 Message Structure
Every PSP Protocol Packet has the same basic structure:
Start Payload Terminator
: {see Section 7.2.5 Payload Contents) <CR>
7.2.4 Binary Packed Messages
Binary Packed messages were considered but the implementation of these was rejected for the following reasons.
• Byte Order
• Floating Point Format
• Floating Point Order
As an alternative to this it will be possible to use block reads for faster data transfer. Another option is to use the RCOV
functionality implemented in this protocol.
7.2.5 Payload Contents
Payload Packets can generally be defined as:Command – parameter 1, parameter 2 <CR>
Three basic types of commands exist:Transferring Data, Setting Parameters and Issuing Control Commands.
Transferring Data Commands
Required Parameter Optional Parameter
Description Command Parameter 1 Parameter 2
Parameter
3
Parameter 4
Read Data from a Data Array in the
ProtoCessor
RD
Data Array
Name
Data Array
Offset
-
FMT (default to decimal
unsigned integer)
Write data to a Data Array in the
ProtoCessor
WD
Data Array
Name
Data Array
Offset
value
FMT (default to decimal
unsigned integer)
Block Read (Future) RB
Data Array
Name
Data Array
Offset
Data
Length
Change Of Value Read RCOV - - -
Change of Value Read and Ack RCOVA - - -
Simple COV ACK A or ACK - - -
ProtoCessor Design Guide 20