Fuji Electric FRENIC-VG Series - Negative Response Frame

5.2 Fuji General-purpose Communications
5-27
Chap. 5 USING STANDARD RS-485
5.2.5 Negative response frame
In cases where the length of the response frame varies according to the command type, if the
command type character is determined properly, the frame length designated for that command is
generally used for the response.
No. Frame/command type Cause of error
Negative response
frame
Error code (M26)
1
Standard frame
Option frame
ENQ not detected in
designated position
Standard frame
(Length: 16 bytes)
Format error:
74 (4AH)
2 Non-designated command
Non-designated command
(not R, W, A, E, a-k, m)
detected
Standard frame
(Length: 16 bytes)
Command error:
75 (4BH)
3
Selecting command (a-f,
m)
ETX not detected in
designated position
Option frame
(Length: 8 bytes)
Format error:
74 (4AH)
4
Polling command
(g-k)
ETX not detected in
designated position
Option frame
(Length: 12 bytes)
Format error:
74 (4AH)
Note: If a negative response such as a format error or command error is returned with a standard frame as
in No. 1 & 2, the contents of the command type, function code type, and function code number fields are
not specified.