ICS ELECTRONICS 9099, Instruction Manual

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3-27
3
L[?] w Loopback Command (code 0x08). Writes a 16-bit word,
w, out to a Modbus device and returns a single response
word to the GPIB bus. The question mark is optional for
smart programs.
(4)
Value for w is 0 to 65535.
D time Timeout Command. Sets timeout value of Modbus response
message in milliseconds. Timeout is the total time for the
message to be received by the 90x9. Value for time is 1 to
65,535 milliseconds. A value of 0 disables the timeout.
The default value is 300 ms. Caution - Do not use 0 or
values that exceed the Network timeout which is normally
3 to 10 seconds.
D? Queries the current timeout setting.
E? Read Error Command. Reads and clears the Modbus Error
Register and bit 6 in the Event Status Register. Returns a
error code whose value is 0 to 255. Current error values
are:
0 No errors present
1-99 Exception Codes 1-99
100 CRC Error
101 Timeout Error indicates no characters
received in the response message.
2nn Partial or corrupted message received.
where nn is the number of received bytes.
Notes:
1. All values are in decimal. To enter HEX values, the value must be preceded with
a #h . i.e. 100 decimal = #h64
2. Response parameter format is set by SCPI FORMat command. Default is ASCii.
3. Do not combine the Modbus commands in Table 3-5 with IEEE-488.2
commands or SCPI commands to avoid query errors or confusing the parser.
4. The [?] is an optional symbol for smart programs like ICS’s VXI-11 Keyboard program
that can recognize the command as a query and automatically read the response
.
5. The IEEE-754 format and RF? register read order is:
TAbLE 3-5 MODbUS COMMANDS CONT'D
Syntax Meaning