The following conditions must be met to use this function.
• The RJ51AW12AL supports this function. ( Page 133 Added or Changed Functions)
• The new slave module supports this function.
• The automatic address detection is performed correctly while "Easy replacement enable/disable setting for one slave
module" is set to "0: Enable" in the module parameter of the RJ51AW12AL. (Parameter information of the slave module is
stored in the RJ51AW12AL.)
• Other slave modules than the one to be replaced have no errors.
• Slave modules with no IDs assigned are not registered.
• 'Adjustment mode executing flag' (XF) turns off.
Turn off the 24VDC external power supply connected to the RJ51AW12AL.
Voltage of the transmission cable drops, and 'Transmission cable voltage drop error' (X3) turns off and on.
Disconnect the slave module to be replaced. (Two or more slave modules cannot be replaced at the same time.)
Connect an unused slave module of the same type. ( Page 41 Applicable slave module)
Turn on the 24VDC external power supply connected to the RJ51AW12AL.
A DP/DN disconnection error occurs, and 'DP/DN disconnection error' (X4) turns off and on.
'One slave module changing flag' (X16) turns off and on, and the backup data is restored from the RJ51AW12AL.
After the backup data is restored, 'One slave module changing flag' (X16) turns on and off, and 'Slave module
replacement completion flag' (X17) turns off and on.
Simultaneously, the error status of the RJ51AW12AL is cleared. (As with turning off and on 'Error flag clear command' (Y0)
(Page 93 Error flag clear command: Y0))
Approximately five seconds later, 'Slave module replacement completion flag' (X17) turns on and off, and the
replacement of the slave module is completed.
• Every time "Easy replacement enable/disable setting for one slave module" is changed from "1: Disable" to
"0: Enable", execute the automatic address detection. Executing the automatic address detection with the
easy one-device replacement enabled stores the device parameters of the slave module to the
• Unless the automatic address detection is executed, the replacement of the slave module will not be
completed successfully, and a malfunction may be caused.
• The easy replacement function for one slave module stops if an error occurs in midstream. Eliminate the
error cause, and follow the procedures from step 1 again.
1.13 Easy Replacement function for One Slave Module