Transmission Path Switching History - Mitsubishi Electric MELSEC Q Series Reference Manual

3.3.3

Transmission path switching history

This section describes details of the transmission path switching history.
The transmission path switching history data are cleared at the time the module is first placed in the loop status after
power-up.
(1) Transmission path switching count (Un\G2784)
The cumulative number of transmission path switching saved in the transmission path switching history is stored.
(2) Transmission path switching history pointer (Un\G2785)
History No. of the latest history is stored.
• 0: No history (No history data)
• 1 or more: History No. of the latest history
When the pointer value is "16", the latest history is registered to History 16.
Ex.
The 17th and subsequent switching will be registered to the histories from History 1 again.
(3) Histories 1 to 16 (Un\G2786 to 2945)
Transmission path switching history data are stored.
Histories 1 to 16 are composed of data in the same arrangement.
(a) Post-switching status
The loop status after transmission path switching is stored.
• 0: Normal
• 1: Loopback
• 2: All station error
(b) No. of connected modules
The number of modules connected to the network is stored.
(c) IN-side loopback station No.
Station No. of the station where a loopback has occurred on its IN-side is stored.
When the Post-switching status is "Normal", "0" is stored.
(d) OUT-side loopback station No.
Station No. of the station where a loopback has occurred on its OUT-side is stored.
When the Post-switching status is "Normal", "0" is stored.
CHAPTER 3 SPECIFICATIONS
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