MATLAB: Do I receive a warning when I run the simulation for a model containing a ‘Find Delay’ block in Simulink 6.0 (R14)

Question

I have a Simulink model containing a Find Delay block, along with a few blocks from the Communications Blockset. In the Simulation–>Configuration parameters dialog, the solver type is selected as 'Fixed Step' and the tasking mode is selected as 'Auto'. When I run the model, I receive the following warning at the MATLAB command prompt:

 Warning: Sample time of enable signal feeding subsystem 'amp_qam16_auto/Find Delay -- only works in Simulation==>config Params==>Single task mode/Compute Delay' is slower than sample times within the enabled subsystem. This can result in nondeterministic behavior in a multitasking real-time system. Consider adding a Rate Transition followed by a Signal Specification with a sample time equal to the enable signal rate.

I do not receive this warning in the following two settings in the Simulation–>Configuration Parameters dialog:

1. Solver type: Variable-step and tasking mode: Auto

2. Solver type: Fixed-step and tasking mode: Single Tasking

Answer 1

This enhancement has been incorporated in Release 2006a (R2006a). For previous product releases, read below for any possible workarounds:

This has been verified as a bug in the Communications Blockset 3.0 (R14) in the way that the Find Delay block handles multi-tasking simulation mode.

Currently, to work around this issue, try running the following command at the MATLAB command prompt:

commstartup

This script will change the simulation tasking mode from 'auto' to 'single'.