Rockwell Automation 1395 Multi-Comm Hardware/Software - Manual (Page 51)

Chapter 3
Configuration & Interfacing
3–40
Read Parameter Data
This function reads parameter value(s) from the Drive based on a
parameter number list provided by the PLC Program. The Drive can
supply up to 30 parameters in one block transfer reply when using the RIO
Read Parameter. The DH+ message can only read one parameter per
request.
PLC Block Transfer Data –
BTW Instruction Length: See below
BTR Instruction Length: See below
PLC DH+ Data –
Write Read
Size In Elements: 5 6
Processor Type: PLC–5 PLC–5
Destination Address: N15:0–4 N15:0–5
Message Structure –
Message Header Information:
Word 1: 0
Word 2: 0
Function Code, Word 3: 514
Write Message Length, Word 4: BTW Word length *2
WORD
0
0
514
See Examples
BTW BTR
0
0
514
See Note
1
2
3
4
NOTE: Word 4 of the BTR instruction is broken down into
two bytes. The High byte contains the status bits
per table 3–H. The low byte contains the Drive
message length in bytes.
Parameter #
Blank
Parameter #
Blank
•
Parameter #
5
6
7
8
•
Parameter #
Parameter Data
Parameter #
Parameter Data
•
Parameter #
Parameter Data
xx
RIO
RIO
DH+ DH+
Message Operation – The READ PARAMETER DATA function
requests the Drive to provide a list of parameter data values for use in the
PLC Controller. The values are returned in Drive units and may need to be
scaled by the PLC Controller prior to being used in the Program.