User`s manual

356
15.5 Switching the Mode from an External Device
This section shows how the Q series C24 mode is switched from an external device.
15.5.1 Mode switching procedure
The following explains the procedure for switching the Q series C24 mode from an external device.
*1 Inform in advance all the connected devices that data communications by mode switching cannot be performed.
*2 When XE and XF were turned on, check the error contents as described in the User's Manual (Basic) and take the
corresponding action.
• Checking of mode switching designation contents for buffer memory mode switching area and writing of mode
switching designation contents within the range that can be designated.
• Re-execution of mode switching
*3 When the mode was switched from an external device, after mode switching is complete, read and write the buffer
memory special applications area shown below from the programmable controller CPU.
• Switch setting error, mode switching error storage area (address: 203H)
• Data communications initialization setting areas (addresses: 93H to 121H /133H to 1C1H) described in the User's
Manual (Basic).
*4 After checking that mode switching was completed normally, inform all the connected devices that data communications
are possible and restart data communications.
*5 For the message format, refer to MELSEC Communication Protocol Reference Manual.
Remark
To check the Q series C24 mode (communication protocol, transmission specifications) after switching, read the buffer
memories (addresses: 252H to 253H, 262H to 263H) described in the User's Manual (Basic).
(To check the external device, read the buffer memory with the MC protocol buffer memory read function.)
*3
*1
*2
*4
*3
X6/XD
XE/XF
X1E
FROM
TO
*5
Mode switching in progress
CH ERR. communication error
Q series C24 ready
Switch setting error, mode switching
error storage area (address 203H)
Programmable
controller CPU
External device
Mode switching
command
message
Mode switching
response
message
Data
communications
possible
(Normal end)
default value modification
(Performed only when necessary)
Data communications impossible Data communicationspossible
(Only when normal)
Approx. 400 ms
Buffer memory special applications area
Data communications initialization
setting area described in
User's Manual (Basic).
Addresses 93H to 121H/133H to 1C1H