Difference between revisions of "CV 181"

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{{Infobox
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{{Infobox CV
|title = NMRA CV 181
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|cv name=BEMF Critical Speed Step
|header1 = DC Mode Sounds
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|cv range=3-126
|label2 = Range of Values
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|cv accepted=3-126
|data2 = 0-255
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|cv default=Varies
|label3 = Default Value
 
|data3 = 255
 
 
}}
 
}}
  
== NMRA CV 181 - DC Mode Sounds ==
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==NMRA CV 181 - BEMF Critical Speed Step==
CV181 controls automatic sounds while operating the WOWDecoder on a DC Analog track. To program this CV take the values in the values column corresponding to the features you want active and sum them together. Program this value into the CV. See the table below for available options
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CV 181 controls at what speed step "inertia takes over" and the BEMF algorithm can change how fast it reacts. The speed/RPM at which this transition occurs will vary based on the type of motor, gear ratio, etc. Usually this speed step is 7 (of 128) or below. This CV is used to set a speed step at which the behaviour of the BEMF changes. Through the use of CV's 178 and 179, you can set up two different levels of "responsiveness" for the BEMF above and below this speed. This feature is most useful with 3-pole and "coreless" motors which tend to have dramatically different BEMF swings depending on the RPM. You may want to have a less sensitive response at slow speeds (below Speed Step 7 for example), but a faster response at higher speeds above 7, or vice-versa.
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{| class="wikitable"
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|!!!WARNING!!! This CV should not be modified unless you are trying to correct a significant issue with slow speed motor control. We do not suggest modifying this CV unless absolutely necessary.
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|}
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This "responsiveness" refers to the motor control itself, not necessarily the sound functions such as chuff intensity or prime mover RPM. Refer to our section on [[Prototype Throttle Mode]] for guidance on BEMF calibration for sound function.
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{| class="wikitable"
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|NOTE: This CV was introduced at different times in different decoders. This CV will not do anything if programmed with a value on a decoder which does not support the feature.
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|}
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Only current-generation decoders (V4.5 Diesel, V4.6 Steam, V90+ Mobile) support this CV and featureset.  
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====Related:====
  
{| class="wikitable" style="text-align: center;"
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*[[CV 177]] - Motor Power Stroke
|-
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*[[CV 178]] - BEMF Speed A
! scope="col"| Feature
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*[[CV 179]] - BEMF Speed B
! scope="col"| Description
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*[[CV 182]]
! scope="col"| Default
 
! scope="col"| Value
 
|-
 
! scope="row"| Automatic Bell
 
| If enabled a bell will sound while moving at low speeds, a safety feature.
 
| ON
 
| 1
 
|-
 
! scope="row"| Forward Horn
 
| If enabled the locomotive will sound two long blasts when starting to move forward
 
| ON
 
| 2
 
|-
 
|-
 
! scope="row"| Reverse Horn
 
| If enabled the locomotive will sound three short blasts when starting to move in reverse
 
| ON
 
| 4
 
|-
 
|-
 
! scope="row"| Stop Horn
 
| If enabled the locomotive will sound one long blast when coming to a stop
 
| ON
 
| 8
 
|-
 
|-
 
! scope="row"| DC Mode Quill
 
| If enabled the locomotive sound a quill when the power pack throttle is flicked up and back down quickly
 
| ON
 
| 16
 
|-
 
|}
 
  
[[Category:DC_Mode]][[Category:Standard_CV]]
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[[Category:DC_Mode]]
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[[Category:Standard_CV]]
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[[Category:Motor]]

Latest revision as of 23:56, 8 September 2022

CV 181
BEMF Critical Speed Step
Range of Values3-126
Accepted Values3-126
Default ValueVaries

NMRA CV 181 - BEMF Critical Speed Step

CV 181 controls at what speed step "inertia takes over" and the BEMF algorithm can change how fast it reacts. The speed/RPM at which this transition occurs will vary based on the type of motor, gear ratio, etc. Usually this speed step is 7 (of 128) or below. This CV is used to set a speed step at which the behaviour of the BEMF changes. Through the use of CV's 178 and 179, you can set up two different levels of "responsiveness" for the BEMF above and below this speed. This feature is most useful with 3-pole and "coreless" motors which tend to have dramatically different BEMF swings depending on the RPM. You may want to have a less sensitive response at slow speeds (below Speed Step 7 for example), but a faster response at higher speeds above 7, or vice-versa.

!!!WARNING!!! This CV should not be modified unless you are trying to correct a significant issue with slow speed motor control. We do not suggest modifying this CV unless absolutely necessary.

This "responsiveness" refers to the motor control itself, not necessarily the sound functions such as chuff intensity or prime mover RPM. Refer to our section on Prototype Throttle Mode for guidance on BEMF calibration for sound function.

NOTE: This CV was introduced at different times in different decoders. This CV will not do anything if programmed with a value on a decoder which does not support the feature.

Only current-generation decoders (V4.5 Diesel, V4.6 Steam, V90+ Mobile) support this CV and featureset.

Related: