Mitsubishi QJ71C24N - Transmission Request Does Not Make the SD LED Blink

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MELSEC-Q
11 TROUBLESHOOTING
11.3.4 Transmission request does not make the "SD" LED blink.
Symptom Cause Corrective action
MC
Bidirectional
Non procedure
Pre-defined
• Due to the OFF status of
the CS(CTS) signal, the Q
series C24 cannot transmit
data to the external device.
• While the CS(CTS) signal is OFF, the Q series C24
does not transmit data to the external device.
It must be ON when the external device is ready to
receive data.
• Although a
transmission request
was made, "SD" does
not blink.
• Due to transmission
control (DTR or DC
control), the external
device cannot receive data.
• Wait until the external device is ready to receive data.
• When the waiting time is too long, check the external
device or cable condition.