# Help with BPM monitor pls

I try to expand my knowledge a bit and accomplish more and more of everything. For a really good training face I would need a working heart rate indicator … On this indicator I would ask for help if I want to monitor a heart rate value between 50 and 200. A value of 50 is at 240 degrees and a value of 200 is at 120 degrees … I would be grateful for a slightly more extensive (but simple English pls…) explanation to understand, not just use. Sorry for the bad English, but google translate knows so much about Hungarian …

This would be my approach to that situation

\$#ZHR#>=50?(-200-(-#ZHR#* 1.6)):-120\$

it should be self expanitory but if you need a breakdown i can ok.

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You could also use the “clamp” function to restrict the rotation angle.

see the documentation for this and other functions:

Expressions – How can we help?

From the documentation:

An expression for rotation that I believe will give you what you want is:

``````(clamp(((#ZHR#-50)*240/150)-120,-120,120))
``````

Explanation:

You want the hand to rotate in the range -120 degrees to 120 degrees for a range of 50 to 200 bpm. That is, 240 degrees of rotation for a range of 150 bpm.

If the pulse rate given by #ZHR# is 50 then the expression: ((#ZHR#-50)*240/150) will = 0, and
if the pulse rate is 200, then the expression will = 240.

If we subtract 120 from the expression then the total value will be:
for 50bpm -120, and
for 200bmp 120

All the clamp function is doing is making sure that if the pulse rate is outside the range 50 to 200 then the hand will not rotate beyond the maximum range -120 to 120 degrees

For example, if the pulse rate is 220bpm then the clamp function will limit the rotation to just 120 degrees.

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THNX Guys!!!

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