PWM Fuel labs Prodigy questions

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cturbo28
Posts: 8
Joined: Thu Aug 13, 2015 2:56 pm

PWM Fuel labs Prodigy questions

Post by cturbo28 »

I had a couple of easy questions for the pros.

Current set up
Scal 2.15.9
Firmware 174.2
S6 with exp I/O

I have installed a Prodigy Pump and would like to run PWM to control the pump for prime and ramp up with rpm and boost, still running a return reg.

Manual for the pump states
500hz-1500hz
PWM pull to ground
0-20% duty pump is off
20-90% pump is variable speed min-max
90%-100% is maximum

My settings
Fuel12 output wired to PWM signal of pump
Relay to turn on pump with key
Prime time 5s
PWM control Enabled
Output drive type = Low side
PWM frequency = 500hz
Off duty= 89% ( pump turns off after prime time, at 90% it cycles every 1 second)
Priming duty=80% (pump does prime at lower speed)
Run duty=50% ( starting car the pump does turn on but low speed, kinda high pitch sound)

My question is This seems backwards from the manual. I tried to set the off duty to 20 but the pump speeds up. It appears it is reverse of the manual.

Am I missing something really simple?
Carter
93 Semi P-port 2 rotor RX7
BW EFR 8374 turbo 1.05
EWP, EPS, DBW
Set up for SSM Auto cross
pat
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Re: PWM Fuel labs Prodigy questions

Post by pat »

Am I missing something really simple?
Yes :)

Low Side output duty is time spent ON, which means LOW. The duty in the fuel pump manual is most likely time spent HIGH, hence the inversion.

IGN (in TTL mode) and HBR output duty (in half bridge mode) is time spent HIGH. Everything else is time spent LOW.

Cheers,

Pat.
cturbo28
Posts: 8
Joined: Thu Aug 13, 2015 2:56 pm

Re: PWM Fuel labs Prodigy questions

Post by cturbo28 »

Thanks Pat,

That seemed to do the job.

Also thanks to Peter for directing the question and the support to fix this issue.
Carter
93 Semi P-port 2 rotor RX7
BW EFR 8374 turbo 1.05
EWP, EPS, DBW
Set up for SSM Auto cross
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