HDC2450 showing 2x current on second channel.

8 years 7 months ago #29530163 by streche
I have a HDC2450 (updated to the latest firmware) driving a small vehicle with two motors on each side. Channel 1 is connected in parallel to the two right motors and channel 2 is connected in parallel to the two left motors.

The vehicle is equally loaded on both sides and drives straight when both channels are commanded equally. (operating in open loop mode)

However the Motor Control Utility shows the Motor Amps 2 being roughly double that of Motor Amps 1. I measured the actual current flowing through each channel using a multimeter and they are drawing the same current (the amount show by Motor Amps 1).

Any ideas why the controller is doubling the current displayed for the second channel?

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8 years 7 months ago #29530165 by LROBBINS
Don't know if this is the case, but here's an hypothesis. Motor current is estimated by (channel battery current)/PWM so is rather inaccurate at low PWM. On top of that, the granularity of the battery current measurement is rather course. I seem to recall a mention in the manual that on higher-amp controllers it's about 1/2 Amp (= 50 deciAmp units). So just a small difference in the circuitry of the two channels could give battery current = 50 on one channel, and battery current = 100 on the other. If PWM is 10%, motor current will then show as 500 and 1000 (5 Amps and 10 Amps) while the real difference might be much smaller.

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8 years 7 months ago #29530171 by TechSupport
Take a look at page 28 and 29 of the user manual. Battery current Vs. Motor current.

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