Appendix. C Network Communication Coordination Using The Fr-A5Np Profibus-Dp Option Module - Mitsubishi Electric FR-A5NP Instruction Manual

Appendix. C
When a command message is sent to the inverter via the FR-A5NP, the
inverter enters a "busy" mode while the command is executed. When a
command message is sent while the inverter is in "busy" mode, that
command is stored in a queue in the FR-A5NP until the inverter finishes
execution of the current command and exits "busy" mode. At that time, the
queued command is issued to the inverter.
If however, a second command message is sent before the queued
command message is accepted by the inverter, the queued message will
be replaced by the succeeding message. In this way, it is possible to "lose"
command messages during network communication. Refer to the
following diagrams for further clarification.
CASE 1
Inverter State
Not Busy
Com Msg
Legend:
A. Inverter ready, Command Message 1 received, inverter begins
executing Command 1 and enters busy mode.
B. Inverter completes execution of Command 1 and exits busy mode.
C. Command
Command 2 and enters busy mode.
D. Inverter in busy mode, Command Message 3 received and buffered
by FR-A5NP module.
E. Inverter completes execution of Command 2 and exits busy mode.
F. Inverter accepts buffered Command 3, begins execution and enters
busy mode.
Network Communication Coordination using
the FR-A5NP PROFIBUS-DP Option Module.
Busy
A
Message 2 received,
51
B C D
inverter begins executing
Appendix
E
F