West Control Solutions ProVU 4 - Manual (Page 82)

ProVU4 Controller, Profiler & Recorder/Controller - Product Manual
59407, Issue 1 – March 2008 Serial Communications Page 81
Function 23 Hex - Read / Write Multiple Registers (0x17 hex)
Reads and writes the requested number of consecutive words (two-bytes) starting at the
specified addresses.
QUERY
Values to Write
Function 1 st Read
Address
Number of
Words to
Read
1 st Write
Address
Number of
Words to
Write 1
st
Word 2
nd
Word etc Last Word
17 HI LO HI LO HI LO HI LO HI LO HI LO → HI LO
RESPONSE
Read Data Function Number of
Bytes 1 st Word 2 nd Word etc Last Word
17 HI LO HI LO HI LO → HI LO
Note:
The number of data that can be read and written in one message is 253 bytes.
Exception Responses
When a QUERY is sent that the instrument cannot interpret then an Exception RESPONSE
is returned. Possible exception responses are:
Exception Code Error Condition Interpretation
00 Unused None.
01 Illegal function Function number out of range.
02 Illegal Data Address Write functions: Parameter number out of range or not
supported. (for write functions only).
Read Functions: Start parameter does not exist or end
parameter greater than 65536.
03 Illegal Data Value Attempt to write invalid data / required action not executed.
The format of an exception response is:
RESPONSE
Function Exception Code
Original Function code with its Most
Significant Bit (MSB) set. as detailed above
Note:
In the case of multiple exception codes for a single QUERY the Exception code returned is
the one corresponding to the first parameter in error.