Mitsubishi Electric FX5-DP-M, User Manual

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APPX
Appendix 3 Buffer Memory
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Data exchange start signals (Un\G2.b0) and (Un\G0.b0)
'Data exchange start request signal' (Un\G2.b0) is turned on when data exchange is started.
When 'Data exchange start request signal' (Un\G2.b0) is turned on and data exchange begins, 'Data exchange start
completed signal' (Un\G0.b0) turns on.
'Data exchange start completed signal' (Un\G0.b0) turns off in one of the following cases.
• 'Data exchange start request signal' (Un\G2.b0) is turned off
• An error causes data exchange to stop
• A communications error occurs to a DP-Slave (When master parameter "Error action flag" is checked)
The signals are used as interlock signals when I/O data are read/written.
Initial values of output data are written to the buffer memory before 'Data exchange start request signal' (Un\G2.b0) is turned
on.
Turn off 'Data exchange start request signal' (Un\G2.b0) clears the information in the following areas. The other buffer
memory areas hold their information.
• 'Slave status area (Normal communication detection)' (Un\G23040 to Un\G23043)
• 'Slave status area (Alarm detection)’(Un\G26416 to Un\G26420)
When 'Data exchange start request signal' (Un\G2.b0) is turned on, the following areas are cleared.
• 'Slave status area (Normal communication detection)' (Un\G23040 to Un\G23043)
• 'Slave status area (Diagnostic information detection)' (Un\G23056 to Un\G23060)
• 'Diagnostic information area' (Un\G23072 to Un\G23199)
• 'Extended diagnostic information area' (Un\G23328 to Un\G23454)
• 'Current bus cycle time area (Un\G2272)'
• 'Minimum bus cycle time area (Un\G2273)'
• 'Maximum bus cycle time area (Un\G2274)'
 Data exchange stopped
 Data being exchanged
OFF
ON
ON
OFF
OFF
OFF
  
'Data exchange start request signal'
(Un\G2.b0)
'Data exchange start completed signal'
(Un\G0.b0)