sepam 20 user manual - Schneider Electric

5
Modbus communication Access to remote settings
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Reply frame
The reply sent back by the Sepam is the same as the remote reading reply frame. It
fits into a zone containing a maximum of 125 words at the address 2000h and is
composed of the effective settings of the function following a semantic check:
2000h-207Ch
B15 B14 B13 B12 B11 B10 B09 B08 B07 B06 B05 B04 B03 B02 B01 B00
Function code Relay number
Settings
..............
(special field for each function)
..............
This zone is read by a "read n words" operation (function 3) at the address 2000h.
The length of the exchange may unclude:
b the first word only (validity test)
b the maximum size of the reply zone (125 words)
b the usable size of the reply zone (determined by the function being addressed).
However, reading must always begin at the first word in the address zone
(any other address triggers an exception reply "incorrect address").
The first word in the reply zone (function code and relay number) has the same
values as those described for the remote reading reply frame.
b xxyy: with:
v function code xx different from 00 and FFh
v relay number yy different from FFh.
The settings are available and validated. The word is a copy of the "request frame".
The zone contents remain valid until the next request is made.
b 0000h: no "request frame" has been formulated yet, as it is the case, in particular,
when the Sepam is switched on.
The other words are not significant.
b FFFFh: the "request frame" has been processed, but the results in the "reply
frame" are not yet available. It is necessary to repeat "reply frame" reading. The other
words are not significant.
b xxFFh: with function code xx different from 00 and FFh. The function for which the
remote reading request has been made is not valid. The function is not included in
that particular Sepam, or access to settings is impossible, both in read and write
mode.
PCRED301005EN - 06/2008