branched signals to merge block

this is the error I am getting when I am connecting a branched signals to merge block

Branched signals cannot be fed into a Merge block. The signal from 'impl_cmd_ctrl_subsys/Implement Command Control v00-/Lift Service Test Manager/Signal Conversion' output port 1 is connected to both Merge block 'impl_cmd_ctrl_subsys/Implement Command Control v00-/Lift Service Test Manager/Merge' input port 1 and to 'impl_cmd_ctrl_subsys/Implement Command Control v00-/Lift Service Testpoints/Subsystem/ImplSvcTstCmd_Fnc_TP/Copy' input port 1. To fix this error, you can insert a Signal Conversion block in Signal Copy mode and feed the output of the Signal Conversion block to only the Merge block. This message is related to a hidden SignalConversion block.

This block is added for block 'impl_cmd_ctrl_subsys/Implement Command Control v00-/Lift Service Test Manager/Signal Conversion' as result of block insertion or expansion. The hidden block's parameter 'Output' is set to 'Signal copy' This message is related to a hidden Merge block.

Answer 1

[Fangjun Jiang]

If a signal line goes to a Merge block, this signal line can't go anywhere else (branched). If you really need to use this signal line somewhere else, insert a Signal Conversion block and set it to do "Signal Copy".

[Dave Hall]

I've tried the Signal Conversion block, but still get the same error. Any idea why?

[Fangjun Jiang]

Not sure if it is the exact "Branched signals cannot be fed into a Merge block" error. My suggestion:

1. The temperature feedback should be taken from the output of the Merge block, then you won't have this problem.

[Dave Hall]

The problem is: I really need the output of the "Heating" block when it was last executed. So when du/dt becomes negative, I need the temperature the last time du/dt was positive for all subsequent calculations. I am surprised that the Signal Conversion block doesn't fix this....that is noted a couple of times as the solution. Another note recommended placing a gain of 1 before the merge block, but that doesn't work either.

[Fangjun Jiang]

Maybe you could try moving the "Signal Conversion" block to the line between the two enabled subsystems. Make sure to set it as "Signal Copy". Set the output of the heating subsystem to be "hold" when not enabled.

[Fangjun Jiang]

Can you attach the model? Simplify it if you need to, as long as the error exists.

[Dave Hall]

Found a fix: I replaced the merge block with a switch block, and that seems to work around the problem. Not as clean as merge, but it works.