"Limit Minimum" syntax help

lardom

I'm building a method that modifies a variable by multiplying it with a 'percentage' value. I want minimum to maximum limits of 100 to 4000.

if percentage <> 0 
  PW := percentage * PW / 100

'PW" is initialized with 1_200. The conditional statement prevents PW from clearing to 0, a fatal error. It would be great if I could put the limits in the CON block.

Sir Gawain

I'm not sure exactly what you want...
Something like this?

CON

PWMAX = 4000
PWMIN = 100

VAR

long PW
long percentage

PUB Main

if percentage <> 0
  'after every new entry to set PW you add:
  PW <#= PWMAX     'limit maximum     see Propeller manual p. 155...
  PW #>= PWMIN     'limit minimum
  'you are validating the input before using it in your code
  PW := percentage * PW / 100

ratronic

Larry if you want to set a lower limit for a variable you can do this -

pw #>= 1000

To limit to a maximum you can do this -

pw <#= 2000

And to limit within a range you can do this -

pw := 1000 #> pw  <# 2000

Edit: You can also do this to limit min/max = pw #> 1000, pw <# 2000

lardom

I'm building a basic Spin encoder object. If the object can handle at least 50 negative edges per second it'll be a good start. I'm trying to keep the code as small as possible.

PUB Main | percentage, PW, CurrentSpeed
    PW := 1_200               
    repeat
      CurrentSpeed := T4.Get_Ticks
      percentage := CurrentSpeed*100/Start_Speed
      if percentage <> 0 
        PW := percentage*PW/100                                                          

Start_Speed = 1600 clocks per negative edge. The CurrentSpeed is compared to 1600 clocks and PW is modified by the same percentage that they don't match. PW can be any number from 1 to 4000. If I could configure the limits as constants I could eliminate at least two lines of code.

lardom

ratronic, just saw your post. Looks good. I'll try it, thanks.

ratronic

You can put your upper and lower limit amounts as CONstants. Also I am correcting the Edit in my post above to show the proper min/max.