Mitsubishi FX3U-232-BD User Manual page 552

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (FX
5.4.3 Command <BFM #1>
BFM #1 gives the command for sending or receiving data or resetting the status information to the 232IF.
Bit
b0 Sending/receiving enable (ER ON)
b1 Sending command
b2 Receiving complete flag reset command
b3 Error reset
1. b0 (sending/receiving enable)
While b0 is ON, the 232IF can send and receive data.
Because the contents of the following set items are determined at the rising edge of b0, transfer these values
in advance using the TO instruction before setting b0 to ON:
- BFM #0 (communication format)
- BFM #9 and 8 (receiving header)
- BFM #11 and 10 (receiving terminator)
At the rising edge of b0, the error occurrence status (BFM #28, b3) and error code (BFM #29) are cleared.
2. b1 (sending command)
At the rising edge of b1, the contents of the send data buffer (BFM #1001 to 1256) in the amount of bytes
specified (BFM #1000) are sent to the external equipment.
When sending is completed, the sending complete status (BFM #28, b0) is set to ON. When the next sending
command (b1) is given, the sending complete status (BFM #28, b0) is automatically set to OFF.
When the sending command is given, the contents of the following set items are determined:
- BFM #5 and 4 (sending header)
- BFM #7 and 6 (sending terminator)
3. b2 (receiving complete flag reset command)
When b2 is set to ON, the following items are cleared:
- BFM #28, b1 (receiving complete)
- BFM #2000 (number of received bytes)
- BFM #2001 to 2256 (receive data buffer)
After receiving is completed, it is necessary to clear the receiving complete status (BFM #28, b1) because the
232IF cannot receive next data while b1 of the BFM #28 remains ON.
When the receiving complete flag reset command is given, the contents of the following set items are
determined:
- BFM #9 and 8 (receiving header)
- BFM #11 and 10 (receiving terminator)
In the RS-232C interlink connection mode (BFM #0, b9 = 1, b8 =1), the receiving complete flag reset
command works as the receiving continue command for receiving data beyond the maximum number of
receivable bytes (BFM #2), and clears the following items:
- BFM #28, b4 (receiving suspended)
- BFM #2000 (number of received bytes)
- BFM #2001 to 2256 (receive data buffer)
- BFM #2257 to 2271 (preliminary receive data buffer)
The receiving enable (RS) signal is automatically set to ON.
4. b3 (error reset)
When b3 is set to ON, the contents of the error occurrence status (BFM #28, b3) and error code (BFM #29)
are cleared.
G-24
-232IF)
2N
Contents
5 Creating Programs
5.4 Buffer Memory (BFM)