Status <Bfm #28 - Mitsubishi Electric MELSEC FX Series User Manual

FX communication
10.2.17 Status <BFM #28>
Bit Description
b0 Send completion
b1 Receive completion
b2 Receive time-out
b3 Error occurrence
b4 Receive suspended
b5 Undefined
b6 Being sent
b7 Being received
The 232IF status and the send/receive result are saved as status information. This information
can be read from the programmable controller using the FROM instruction.
1 ) b0 (send completion)
When send of data up to the send byte count (BFM #1000) is completed, the send
completion status (b0) is set. The send completion status (b0) is automatically reset when
the next send command (BFM #1 b1) set to "ON".
2 ) b1 (receive completion)
When receive of data up to the receive upper limit byte count (BFM #2) is completed, the
receive completion status (b1) is set. If the receive terminator (BFMs #11 and #10) or the
receive time-out time (BFM #3) is set, it is regarded that receive is completed when the set
condition is satisfied, then the receive completion status (b1) is set in the same way.
This status is required to be reset using the sequence program. If it is not reset, the next data
cannot be received. This status can be reset using the receive completion reset command
(BFM #1 b2).
3 ) b2 (receive time-out)
When the receive time-out time (BFM #3) is reached while data is received, the receive time-
out status (b2) is set. At the same time, the receive completion status (b1) is also set.
This status is automatically reset when the receive completion reset command (BFM #1 b2)
is executed.
4 ) b3 (error occurrence)
When an error occurs while data is sent or received, b3 is set to "ON" and the error is saved
to the error code (BFM #29).
5 ) b4 (receive suspended)
When data exceeding the receive upper limit byte count (BFM #2) is received in the RS-232C
interlink connection mode (BFM #0 b9=1, b8=1), the 232IF sets the request to send (RS)
signal to "OFF", requests the counterpart equipment to suspend the send operation, then
sets b4 after the receive suspension waiting time (BFM #12) has expired.
To receive the excess data in the interlink connection, the rising edge of the b4 is required to
be monitored using the sequence program. The data as much as the receive byte count
(BFM #2000) in the receive buffers (BFMs #2001 to #2271) or the data as much as the
number of receive buffers (BFM #14) should be read to data registers in the programmable
controller and the receive completion command executed (BFM #1 b2).
6 ) b6 (being sent)
b6 is turned on after the send command (BFM #1 b1) is given until the send completion
status (BFM #28 b0) is set.
Bit Description
b8 RS (RTS)
b9 ER (DTR)
b10 Undefined
b11 Undefined
b12 DR (DSR)
b13 CD (DCD)
b14 DS (CTS)
b15 CI (RI)
FX -232IF 10
2N
10
10-13