Online Module Selection Error Flag (ON)

What does SM1618 mean?

This flag turns on when an error occurs during the module selection phase of an online module change. It indicates that an incorrect module has been specified or an invalid I/O number has been used, preventing the 'Online module changing status' (SD1617) from progressing to Module selection completion (2). The specific error is generally detailed in 'Online module change error code' (SD1618) but root causes are provided here.

• A module that does not support the online module change function has been specified for online replacement.
• An I/O number specified using 'Module selection (base No.)' (SD1600) and 'Module selection (slot No.)' (SD1601) corresponds to a slot where no module is mounted.
• A module currently under the control of another CPU module has been specified as the target for online change.

Click steps to track your progress.

1. 1

   If the module to be replaced does not support online module change, power off the programmable controller completely before performing the replacement.

2. 2

   Correct the specified base unit number in 'Module selection (base No.)' (SD1600) and the slot number in 'Module selection (slot No.)' (SD1601) to accurately reflect the target module.

3. 3

   Set 'Online module change error code' (SD1618) to 0 to clear any previous error information.

4. 4

   Turn off 'Online module change error flag' (SM1618) and 'Module selection request flag' (SM1600) to reset the online module change process.

5. 5

   If the specified module is controlled by another CPU, initiate the online module change from the CPU module or remote head module that maintains control over it.

6. 6

   If the 'Online module change error flag' (SM1618) is off but 'Online module changing status' (SD1617) does not reach Module selection completion (2), consider replacing the CPU module or remote head module.