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Troubleshooting Z Motor Positive soft limit too nonlinear at innermost test point on the MiSeq
The following Z stage/motor error indicates either a temporary communication loss between the stage and software or an issue with the stage hardware.
Error: “Z Motor: Positive soft limit too nonlinear even at innermost test point: Target = -20.000 um, actual = -16.287 um, error = 3.713 um, tolerance = 0.100 um (System.Exception)”
This error usually occurs at cycle 1 of a sequencing run, after a power cycle, or at the start of a wash.
**Troubleshooting Steps:**1. Complete the post-run wash if not already completed. 2. Power cycle* the instrument. 3. If the system initializes, run the Z stage Test in the System checks 5 times to verify the stage is moving correctly.
- MiSeq Control Software (MCS) v4.0: From Main Menu, select System Check.
- MCS v3.1 and older: From Welcome Screen, select Manage Instrument, select System Check.
- Follow the prompts on the screen to start the test, and repeat the test 4 more times (5 times total).
*For further information, search for Knowledge Base articles How to Shut down or power cycle the MiSeq and How To Power Cycle the MiSeq Video.