Mitsubishi MELSEC Q Series User Manual

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4.4 MELSECNET/H Module Access Function
4.4.1 Message communication
4
FUNCTIONS
(a) Internal buffer for message reception
1) The internal buffer for message reception stores the data received from the
MELSECNET/H module controlled by the C Controller module.
2) The internal buffer for message reception has areas for four MELSECNET/H
modules, and in each of the areas, up to 128 received data can be stored.
When data are received, however, the internal buffer has been full of stored
data, the incoming data are discarded and are not be stored into the internal
buffer for message reception.
Read the received data before the number of data stored in the internal buffer
for message reception exceeds 128.
3) In message reception, the reception data stored into the internal buffer first is
fetched first, corresponding to the channel specified by the message receiving
function.
Figure 4.12 Internal buffer for message reception
ret = QBF_RECV();
ret = mdReceive();
(For second module)
(For third module)
(For fourth module)
1st
2nd
127th
128th
1st
2nd
127th
128th
1st
2nd
127th
128th
1st
2nd
127th
128th
MELSECNET/H module (Second)
MELSECNET/H module (Third)
MELSECNET/H module (Fourth)
C Controller module
for message reception
MELSECNET/H module
Internal buffer User program
or
Logical channel (Channel 1)
Logical channel (Channel 2)
Logical channel (Channel 3)
Logical channel (Channel 4)
Logical channel (Channel 5)
Logical channel (Channel 6)
Logical channel (Channel 7)
Logical channel (Channel 8)
MELSECNET/H module (First)

Mitsubishi MELSEC Q Series Specifications

General

Brand	Mitsubishi
Model	MELSEC Q Series
Category	Controller
Language	English