The alternative is to limit the max PWM duty cycle after the signal has left the SUM. So now I am

**trying to come up with dummy loads for the SUM**, so that not having the dampers connected directly to the SUM will not cause the SUM to err out and shut down.

**Last night I succeeded.**

I used a 5 ohm 25W wirewound ceramic resistor. WARNING: ITS POWER HANDLING CAPACITY IS MARGINAL, AT BEST.

In series with the resistor I connected an inductor:

each of these weighs 4~5 oz:

I was surprised and disappointed to see that the SUM's output changed drastically; where the 'relaxed'/base duty cycle in Comfort mode in my caR is typically around 16%, switching over to the 5-ohm-plus-coil dummy load caused the SUM's duty cycle to be much higher. Each of the 2 coils with similar labeling raised the duty cycle to 33%. The slightly smaller coil yielded 40%. If I connected the two "33%" coils in parallel (in series with the resistor), the SUM erred out. If I put the 40 in parallel with a 33, I could get a somewhat jittery 28%. Output to the dummy load in Sport was proportionally higher; Advanced was higher still; with some coils I saw percentages in the 80s and 90s. (This means that the 25W resistor is seeing roughly twice as much power as I'd figured, oops.)

So this early attempt at coming up with a SUM dummy load seems sufficient to keep the SUM from erring out (at least for a ride around the block) when it's not connected to a 4C damper, but insufficient to allow me to intercept an unaltered SUM PWM output signal and filter/modify it before passing it along to the dampers...

-- 100th post --