Mitsubishi Electric Q03UDVCPU User Manual page 94

(d) Precaution for Active open communication
Configure an interlock circuit using the Open completion signal (SD1282) and Open request signal (SD1284) in
the program.
The following chart shows on/off timings of the Open completion signal and Open request signal.
Open completion signal
(SD1282)
Open request signal
(SD1284)
92
ON
OFF
ON
OFF
SOCOPEN instruction
<When disconnected by the CPU module>
TCP disconnection completed upon
response from the external device
TCP disconnection request from the CPU module
SOCCLOSE instruction
<When disconnected by the external device>
TCP disconnection request from the external device
TCP disconnection completed upon
response from the CPU module
SOCCLOSE instruction