Jumper Ramps 1.4 & Vref January 11, 2016 01:09PM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 11, 2016 02:44PM |
Registered: 10 years ago Posts: 3,268 |
Re: Jumper Ramps 1.4 & Vref January 11, 2016 03:15PM |
Registered: 10 years ago Posts: 6,409 |
Re: Jumper Ramps 1.4 & Vref January 12, 2016 04:55AM |
Registered: 10 years ago Posts: 3,268 |
Re: Jumper Ramps 1.4 & Vref January 12, 2016 08:21AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 12, 2016 08:41AM |
Registered: 10 years ago Posts: 6,409 |
Re: Jumper Ramps 1.4 & Vref January 12, 2016 08:50AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 15, 2016 09:11AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 15, 2016 10:03AM |
Registered: 10 years ago Posts: 3,268 |
Re: Jumper Ramps 1.4 & Vref January 15, 2016 02:56PM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 15, 2016 03:11PM |
Registered: 10 years ago Posts: 3,268 |
Another way to set the current limit is to measure the voltage on the “ref” pin and to calculate the resulting current limit (the current sense resistors are 0.100Ω). The ref pin voltage is accessible on a via that is circled on the bottom silkscreen of the circuit board. The current limit relates to the reference voltage as follows: Current Limit = VREF × 2 So, for example, if the reference voltage is 0.5 V, the current limit is 1 A. As mentioned above, in full step mode, the current through the coils is limited to 70% of the current limit, so to get a full-step coil current of 1.5 A, the current limit should be 1.5 A/0.7=2.1 A, which corresponds to a VREF of 2.1 A/2=1.05 V. See the DRV8825 datasheet for more information.
Re: Jumper Ramps 1.4 & Vref January 16, 2016 10:19AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 16, 2016 11:08AM |
Registered: 10 years ago Posts: 6,409 |
I_TripMax= Vref / ( 8 * Rs) Rs = 0,05 ohm 8 * 0.05 = 0.4 --> 1 / 0,4 = 2,5 I_TripMax= Vref * 2,5
I_TripMax= Vref * 2
Re: Jumper Ramps 1.4 & Vref January 16, 2016 11:18AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 16, 2016 11:23AM |
Registered: 9 years ago Posts: 75 |
Re: Jumper Ramps 1.4 & Vref January 16, 2016 11:27AM |
Registered: 10 years ago Posts: 6,409 |