Difference between revisions of "SnapAmp Info"
From Dynomotion
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==Peak Current Settings== | ==Peak Current Settings== | ||
<span style="font-family: Arial;">When SnapAmp Powers up the Peak Current settings will not be set and consequently the boards will be in Current Fault mode with the Fault LED on. Some C Code is required to set the Peak Current Limits and bring the board out of fault mode. See: Approximate Peak Current Thresholds [http://www.dynomotion.com/Help/SchematicsSnap/UsingSnapAmp.htm here].</span> | <span style="font-family: Arial;">When SnapAmp Powers up the Peak Current settings will not be set and consequently the boards will be in Current Fault mode with the Fault LED on. Some C Code is required to set the Peak Current Limits and bring the board out of fault mode. See: Approximate Peak Current Thresholds [http://www.dynomotion.com/Help/SchematicsSnap/UsingSnapAmp.htm here].</span> | ||
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| + | ==<span id="Drive_Enables_-_Axis_Drift_with_Servo_Disabled_-_Power_up_Issues" class="mw-headline">Drive Enables - Axis Drift with Zero Current Commanded - PWMC Commands<br /></span>== | ||
| + | <span class="mw-headline">The SnapAmp PWMC command goes into PWM switching mode attempting to regulate zero current by measuring the current (an analog signal) and adjusting the voltage (PWM). This is a problem with any analog signal/drive. Analog signals are imperfect and will always have bias, nonlinearities, noise, etc. The SnapAmp Current measurement/control range is +/-35 Amps (a 70 Amp full range). With such a large range extreme precision is required to control exact zero current. ie even a 0.1% error = 0.07Amps. SnapAmp wasn't designed for that high of accuracy as it isn't needed to control a motor well. Once the servo is enabled the servo will command whatever current is required to hold the motor in position.</span> | ||
Revision as of 13:20, 21 July 2016
SnapAmp is a Multi-purpose Multi-Axis Amplifier board for KFLOP
| SnapAmp Plotting Example |
Peak Current Settings
When SnapAmp Powers up the Peak Current settings will not be set and consequently the boards will be in Current Fault mode with the Fault LED on. Some C Code is required to set the Peak Current Limits and bring the board out of fault mode. See: Approximate Peak Current Thresholds here.
Drive Enables - Axis Drift with Zero Current Commanded - PWMC Commands
The SnapAmp PWMC command goes into PWM switching mode attempting to regulate zero current by measuring the current (an analog signal) and adjusting the voltage (PWM). This is a problem with any analog signal/drive. Analog signals are imperfect and will always have bias, nonlinearities, noise, etc. The SnapAmp Current measurement/control range is +/-35 Amps (a 70 Amp full range). With such a large range extreme precision is required to control exact zero current. ie even a 0.1% error = 0.07Amps. SnapAmp wasn't designed for that high of accuracy as it isn't needed to control a motor well. Once the servo is enabled the servo will command whatever current is required to hold the motor in position.
