Rockwell Automation 1336-GM1 Remote I/O Communications Module - Manual (Page 67)

Supported Block Transfer Messages B–3
Parameter Value Read Parameter Value Read reads the 16-bit parameter data value for the
selected parameter number.
PLC Block Transfer Instruction Data
PLC request instruction length: 3 words
Drive response instruction length: 4 words
Figure B.3 Message Structure
Message Operation
Parameter Value Read reads parameter values from the drive and
places that value (or an error code) in word 3 of the drive response
data file. The value is shown in device units. Device units are listed in
the user manual for the device you are using.
If an error occurs:
• Word 3 of the response contains the status code.
• The status area of the data file is non-zero.
Example
In this example, the value of parameter 20 was requested from a 1336
PLUS drive and a value of 4096 was returned. 4096 is the internal
drive unit value for Maximum Rated Voltage. This corresponds to a
value of 100% Drive Rated Volts in Display Units.
Data File Format
* Example only — These values vary depending on parameters and products.
PLC Decimal Value
769
PLC Request
Header Word 0
Header Word 1
Header Word 2
Parameter Value or
Message Length
Drive Response
Parameter Number
3
(See Drive List)
Error Code
Message Length
PLC Decimal Value
Parameter Number
769=OK –31999=Error
Header
Word 0
Header
Word 1
Header
Word 2
Data
Word 3
4
0 1 2 3 4 5 6 7 8 9
PLC request 3 769 20*
Drive response 4 769 20* 4069*