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9 CONTENTS AND REGISTRATION OF THE USER FRAMES FOR DATA
COMMUNICATION
MELSEC-Q
9.3 Precautions when Registering, Reading, Deleting and Using User Frames
The following shows the precautions which should be observed when registering user frames and using registered user frames to transmit data to and receive data correctly from the external device.
(1) Precautions when registering, reading or deleting user frames
(a) User frames can be registered using one of the following methods. However, an user frame to be registered to the flash ROM could be registered by the utility package (GX Configurator-SC) dedicated to the Q series C24 as much as possible.
1) Registering via the utility package (GX Configurator-SC) for the Q series
C24.
2) Registering with the dedicated instruction "PUTE" from the PLC CPU.
3) Registering from an external device with command "1610" through communication using the MC protocol.
(b) The following settings are required when registering or deleting user frames.
1) Switch setting via GX Developer
Set the setting modification to Enable in the transmission setting.
2) Setting via GX Configurator-SC
Set the flash ROM write allow/prohibit setting to Allow on the monitor/test screen.
To set from the PLC CPU, write "1" in the following buffer memory at the startup of the Q series C24 (when the ready signal rises).
Flash ROM write allow/prohibit designation area (address: 2000
H
)
(c) To register, read or delete user frames from the PLC CPU, perform the operation while there is no data communication in progress with the external device.
(d) An user frame having only a sum check code as changeable data cannot be registered. To register a sum check code, add arbitrary data.
(e) Register a receive user frame in the Q series C24 flash ROM.
(f) The changeable data (05
H
to F9
H
) can be specified at only one place in the last frame.
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9 CONTENTS AND REGISTRATION OF THE USER FRAMES FOR DATA
COMMUNICATION
MELSEC-Q
(2) Precautions when using user frames
(a) To send/receive data using the user frames, it is necessary to set the user frame number to be used in the buffer memory prior to data transmission/reception (receive user frames must be set at the startup of the
Q series C24).
The user frame number to be used can be set from the PLC CPU. However, please try to register frames using the utility package (GX Configurator-SC) of the Q series C24.
(b) Set the receive user frame number by the PLC CPU to show the procedure to receive data.
Receive user frame data by performing the following operations sequentially.
(chapter 11 explains steps 2) and 3).)
1) If an user frame used in data reception was registered from PLC CPU, restart PLC CPU.
2) When starting the Q series C24, set the receive user frame No. to the buffer memory and write [1] to buffer memory user frame use enable/disable designation area (addresses: AD
H
/14D
H
).
3) After the value of the buffer memory user frame use enable/disable designation area changes to [2], start receiving data.
4) Check if the data from the external device was received normally.
(c) If the Q series C24 receives additional code data while receiving data with the non procedure protocol, it does not assume that the last byte of data is the following control data.
• Data received as user frame first frame, last frame (See Sections 9.1 and
9.2.)
• Receive complete code data
Therefore, do not set a user frame containing data receive additional code data as a non procedure protocol receive user frame.
(d) The arbitrary data area of a message received from an external device cannot include data with the same contents (same code) as the last frame.
(Example)
User frame
(first frame)
Arbitrary dat area
User frame
(last frame)
(e) In the following cases, set the data bit length of the transmission specification to 8 bits.
(It is set in the "transmission setting" of switch setting by GX Developer on the Q series C24 side.)
1) When transmitting and receiving the sum check code of the variable data as binary data
(Write code: FF
H
, EE
H
/FF
H
, F0
H
/FF
H
, F4
H
/FF
H
, F6
H
)
2) When transmitting and receiving a user frame containing data codes 80
H to FF
H
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