Example Of Creating A Structured Program - Mitsubishi Electric MELSEC Q Series Programming Manual

Example of creating a structured program

This section shows an example of creating a sequence program same as the program created in GX Developer using GX
Works2.
Ex.
The following examples explain the method for creating a structured program same as the data receive program for a Q-
compatible serial communication module, using the structured ladder/FBD and ST languages.
The following shows the original program.
Replacing devices with labels
Replace devices of the original program with labels.
Replace input/output devices with global labels. For devices such as internal relays, replace them with local labels.
Device Purpose
X3 CH1 reception data read request
X4 CH1 reception abnormal detection
D0 Control data
D1
D2
D3
D10 to D109 Reception data
D110 to D209 Reception data storage area
M0 Data reception
completion flag
M1
M100 Abnormal completion flag
X100 Abnormal completion flag reset command
APPX
104
Appendix 3 Recreating Ladder Programs
Reception channel
Reception result
Number of reception data
Number of allowable reception data
Completion flag
Status flag at completion
Specify the receive channel.
Clear the reception result and receive data count
storage device to 0.
Specify the allowable receive data count.
With normal completion, the receive data within the
allowable receive data count (user specified) is read
from the receive data storage area in the buffer memory.
• Once the INPUT instruction is executed, the user
specified read completion signal (M0) turns ON for
1 scan.
• The reading of receive data and switching of the
ON/OFF status are performed by the programmable
controller CPU.
The abnormal completion flag is reset by an external
command.
Label
Data type Label name
Bit CH1ReadRequest
Bit CH1AbnormalDetection
Word (unsigned)/16-bit string ControlData
[0] to [3]
Word (unsigned)/16-bit string ReceiveData
[0] to [99]
Word (unsigned)/16-bit string Data
[0] to [99]
Bit [0] to [1] Completion
Bit AbnormalCompletion
Bit ResetAbnormalCompletion