retepsnikrep
- 19th September 2013, 02:42
Dear Members
I have an 8mhz 12F683 monitoring a 2khz pwm signal. I am using pulsin to determine the high time and at 8mhz I get 5us resolution or 100 units over a 2khz 500us pulse. That's all fine.
I also have two rail to rail pots being monitored by 8 bits adc's and then multiplied to give 0-100 units resolution.
Again that's fine.
I am also using the pic HPWM to duplicate the incoming pwm data stream multiplying the incoming puslin data to provide the 8 bit hpwm data reqd. That's fine.
What I am doing is modifying the incomming pwm data using the two pots and then sending the modified pwm out of the hpwm.
The issue is my maths and logic seems horribly complicated.
Lets take a pwm signal with a high time of 51-90% I want to modify that with one of the pots called AssistPot so that
The first pot called AssistPot is only reqd to work on signals with a duty of 51-90%
1) When the pot is at 50% (in the middle) then it has no effect on the signal.
2) When it is 51-100% I want it to lengthen the pwm high time by 0-100% upto a maximum of 90% duty.
3) When it is 49-0% I want it to shorten the pwm high time by 0-100% down to a minimum of 51% duty.
The second pot called RegenPot does something similar but is reqd to only works on signals with a duty of 49-10%
1) When the pot is at 50% (in the middle) then it has no effect on the signal.
2) When it is 51-100% I want it to shorten the pwm high time by 0-100% down to a minimum of 10% duty.
3) When it is 49-0% I want it to lengthen the pwm high time by 0-100% upto to a maximum of 49% duty.
Now my code below works but feels clunky and I had to add a couple of checks to stop the maths going negative.
I think there must be a more elegant solution. The RegenPot maths seemed much harder.
I have it working using the code below and proteus simulates correctly. It also works with my hardware.
So I'm really looking for improvements, coding tricks or other brilliant insight :?
pulsin CmdPwrIn,1,CmdPwrHigh 'Measures length of Incoming CmdPwr 2khz Pwm Duty High pulse
If CmdPwrHigh > 50 then 'Assist Requested Duty > 50%
PwrLevel = CmdPwrHigh - 50
High Led 'Turn On Red Assist Led
ADCIN 0,AssistPot 'Get AssistPot Setting
AssistPot = (AssistPot * 100) / 255
If AssistPot > 50 then
AssistPot = AssistPot - 50
Multiplier = 100 + ((AssistPot * 100) / (100 - AssistPot))
PwrLevel = 50 + ((Pwrlevel * Multiplier)/100)
elseIf AssistPot < 50 then
AssistPot = 50 - AssistPot
Multiplier = 100 + ((AssistPot * 100) / (100 - AssistPot))
PwrLevel = 50 + (PwrLevel-(((Pwrlevel * Multiplier)/100)-Pwrlevel))
elseif AssistPot = 50 then
AssistPot = 0
PwrLevel = CmdPwrHigh
endif
endif
If CmdPwrHigh < 50 then 'Regen Requested Duty < 50%
PwrLevel = 50 - CmdPwrHigh
low Led 'Turn On Green Regen Led
ADCIN 1,RegenPot 'Get RegenPot Setting
RegenPot = (RegenPot * 100) / 255
If RegenPot > 50 then
RegenPot = RegenPot - 50
Multiplier = 100 + ((RegenPot * 100) / (100 - RegenPot))
General16 = ((Pwrlevel * Multiplier)/100)
if General16 > 50 then General16 = 50 'Prevents Result Negative Overflow error
PwrLevel = 50 - General16
elseIf RegenPot < 50 then
RegenPot = 50 - RegenPot
Multiplier = 100 + ((RegenPot * 100) / (100 - RegenPot))
PwrLevel = 50 - (PwrLevel-(((Pwrlevel * Multiplier)/100)-PwrLevel))
elseif RegenPot = 50 then
RegenPot = 0
PwrLevel = CmdPwrHigh
endif
endif
If CmdPwrHigh = 50 then
TRISIO.4 = 1 'Turn Off Led
PwrLevel = 128
else
if Pwrlevel > 90 then PwrLevel = 90 'Prevent Assist request Error Duty > 90%
if PwrLevel < 10 then PwrLevel = 10 'Prevent Regen request Error Duty < 10%
PwrLevel = (PwrLevel * 255) / 100 'Calculate HPWM Duty 8 bit data
endif
Any Ideas?
I have an 8mhz 12F683 monitoring a 2khz pwm signal. I am using pulsin to determine the high time and at 8mhz I get 5us resolution or 100 units over a 2khz 500us pulse. That's all fine.
I also have two rail to rail pots being monitored by 8 bits adc's and then multiplied to give 0-100 units resolution.
Again that's fine.
I am also using the pic HPWM to duplicate the incoming pwm data stream multiplying the incoming puslin data to provide the 8 bit hpwm data reqd. That's fine.
What I am doing is modifying the incomming pwm data using the two pots and then sending the modified pwm out of the hpwm.
The issue is my maths and logic seems horribly complicated.
Lets take a pwm signal with a high time of 51-90% I want to modify that with one of the pots called AssistPot so that
The first pot called AssistPot is only reqd to work on signals with a duty of 51-90%
1) When the pot is at 50% (in the middle) then it has no effect on the signal.
2) When it is 51-100% I want it to lengthen the pwm high time by 0-100% upto a maximum of 90% duty.
3) When it is 49-0% I want it to shorten the pwm high time by 0-100% down to a minimum of 51% duty.
The second pot called RegenPot does something similar but is reqd to only works on signals with a duty of 49-10%
1) When the pot is at 50% (in the middle) then it has no effect on the signal.
2) When it is 51-100% I want it to shorten the pwm high time by 0-100% down to a minimum of 10% duty.
3) When it is 49-0% I want it to lengthen the pwm high time by 0-100% upto to a maximum of 49% duty.
Now my code below works but feels clunky and I had to add a couple of checks to stop the maths going negative.
I think there must be a more elegant solution. The RegenPot maths seemed much harder.
I have it working using the code below and proteus simulates correctly. It also works with my hardware.
So I'm really looking for improvements, coding tricks or other brilliant insight :?
pulsin CmdPwrIn,1,CmdPwrHigh 'Measures length of Incoming CmdPwr 2khz Pwm Duty High pulse
If CmdPwrHigh > 50 then 'Assist Requested Duty > 50%
PwrLevel = CmdPwrHigh - 50
High Led 'Turn On Red Assist Led
ADCIN 0,AssistPot 'Get AssistPot Setting
AssistPot = (AssistPot * 100) / 255
If AssistPot > 50 then
AssistPot = AssistPot - 50
Multiplier = 100 + ((AssistPot * 100) / (100 - AssistPot))
PwrLevel = 50 + ((Pwrlevel * Multiplier)/100)
elseIf AssistPot < 50 then
AssistPot = 50 - AssistPot
Multiplier = 100 + ((AssistPot * 100) / (100 - AssistPot))
PwrLevel = 50 + (PwrLevel-(((Pwrlevel * Multiplier)/100)-Pwrlevel))
elseif AssistPot = 50 then
AssistPot = 0
PwrLevel = CmdPwrHigh
endif
endif
If CmdPwrHigh < 50 then 'Regen Requested Duty < 50%
PwrLevel = 50 - CmdPwrHigh
low Led 'Turn On Green Regen Led
ADCIN 1,RegenPot 'Get RegenPot Setting
RegenPot = (RegenPot * 100) / 255
If RegenPot > 50 then
RegenPot = RegenPot - 50
Multiplier = 100 + ((RegenPot * 100) / (100 - RegenPot))
General16 = ((Pwrlevel * Multiplier)/100)
if General16 > 50 then General16 = 50 'Prevents Result Negative Overflow error
PwrLevel = 50 - General16
elseIf RegenPot < 50 then
RegenPot = 50 - RegenPot
Multiplier = 100 + ((RegenPot * 100) / (100 - RegenPot))
PwrLevel = 50 - (PwrLevel-(((Pwrlevel * Multiplier)/100)-PwrLevel))
elseif RegenPot = 50 then
RegenPot = 0
PwrLevel = CmdPwrHigh
endif
endif
If CmdPwrHigh = 50 then
TRISIO.4 = 1 'Turn Off Led
PwrLevel = 128
else
if Pwrlevel > 90 then PwrLevel = 90 'Prevent Assist request Error Duty > 90%
if PwrLevel < 10 then PwrLevel = 10 'Prevent Regen request Error Duty < 10%
PwrLevel = (PwrLevel * 255) / 100 'Calculate HPWM Duty 8 bit data
endif
Any Ideas?