User`s manual

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15.1.2 Operation for mode switching
The following describes the Q series C24 operation for mode switching.
(1) Processing currently in execution
(a) If there is a mode switching request, mode switching immediately starts.
(b) If one of the following processing was being performed when a mode switching
request was issued, that processing is terminated.
• Data communications using an MC protocol
• Command message receive processing and response message or on-demand data transmission
processing are all terminated.
• The transmission complete end signal for an on-demand data transmission request is not turned on.
• Data communications using non procedure, bidirectional, or pre-defined protocol
• Data and response message transmit and receive processing are all terminated.
• All the input signals from the programmable controller CPU related to transmit and receive processing are
turned off.
• If the receive data from the external device was being stored to the Q series C24, the receive data up to
that point is ignored and the data is processed with the current receive data count as [0].
(2) Modification of buffer memory stored value
(a) Special applications area (addresses: 252H to 253H, 262H to 263H)
The communication protocol status and transmission specifications after mode switching is complete are
stored.
The values stored to areas other than the above are not changed. The contents before switching are
preserved.
(b) User free area (addresses: 400H to 1AFFH, 2600H to 3FFFH)
The stored values are not changed. The contents before mode switching are preserved.