Power Circuit Questions for DF15RMG
matt.b 2019-05-14 15:44:43 3653 Views2 Replies Hi,
My company purchased 5 units of DF15RMG last week, and if they perform well during evaluation we'll purchase 100's more at least.
But we're new to servos and have a couple questions about how they should be connected up for power and control. Please see the attached figure for a simplified circuit diagram.
Our questions:
1 - If we're powering the servo from a 2S LiPo, is it ok to just connect them directly to each other? Is there any need or improvement to add some additional passive components like decoupling capacitors if the motor is 30 to 100 cm from the battery? What about safety components like kickback diodes? Basically is there anything we should design in to the circuit other than a straight wire from the battery positive terminal to the servo positive input line? Does this change at all if there are several of the same servos in parallel?
2 - Similar for the PWM control signal: Is the ideal implementation just to directly connect the PWM output from the microcontroller to the control input line of the servo with no other components involved?
3 - The reason we have a separate battery for the microcontroller is that there are many other small loads on that battery that aren't shown, but also... our implementation has a few servo motor groups (not shown in diagram) that are each about 1 meter distant from the microcontroller which is at the center, so a sort of physical 'star topology'. We were thinking that to reduce I-squared-R (Ohmic) losses in the wires due to the large servo currents we should put one LiPo physically near to each servo motor group. BUT we still want to tie all the LiPo's electrically in parallel so that the batteries can all 'help each other' if for example one servo motor group gets heavier demand than the others. Is this idea for spreading the batteries physically apart a good idea, or should we put all the batteries at the same physical location and tie them together in parallel before connecting to the overall power rail?
Sorry so long - we're experienced electrical engineers but have never worked with servos before and don't want to design any circuits that result in sub-optimal performance or service life for the servos or batteries.
Thanks very much!
Matt
PS - For some reason your system is not letting me attach the diagram even though it's just a small .png file. I'll try again after posting this message, but if it's not here when you read this could you please email me so I can send it to you via email? It's probably very helpful to the conversation to refer to that diagram. My email is [email protected]
My company purchased 5 units of DF15RMG last week, and if they perform well during evaluation we'll purchase 100's more at least.
But we're new to servos and have a couple questions about how they should be connected up for power and control. Please see the attached figure for a simplified circuit diagram.
Our questions:
1 - If we're powering the servo from a 2S LiPo, is it ok to just connect them directly to each other? Is there any need or improvement to add some additional passive components like decoupling capacitors if the motor is 30 to 100 cm from the battery? What about safety components like kickback diodes? Basically is there anything we should design in to the circuit other than a straight wire from the battery positive terminal to the servo positive input line? Does this change at all if there are several of the same servos in parallel?
2 - Similar for the PWM control signal: Is the ideal implementation just to directly connect the PWM output from the microcontroller to the control input line of the servo with no other components involved?
3 - The reason we have a separate battery for the microcontroller is that there are many other small loads on that battery that aren't shown, but also... our implementation has a few servo motor groups (not shown in diagram) that are each about 1 meter distant from the microcontroller which is at the center, so a sort of physical 'star topology'. We were thinking that to reduce I-squared-R (Ohmic) losses in the wires due to the large servo currents we should put one LiPo physically near to each servo motor group. BUT we still want to tie all the LiPo's electrically in parallel so that the batteries can all 'help each other' if for example one servo motor group gets heavier demand than the others. Is this idea for spreading the batteries physically apart a good idea, or should we put all the batteries at the same physical location and tie them together in parallel before connecting to the overall power rail?
Sorry so long - we're experienced electrical engineers but have never worked with servos before and don't want to design any circuits that result in sub-optimal performance or service life for the servos or batteries.
Thanks very much!
Matt
PS - For some reason your system is not letting me attach the diagram even though it's just a small .png file. I'll try again after posting this message, but if it's not here when you read this could you please email me so I can send it to you via email? It's probably very helpful to the conversation to refer to that diagram. My email is [email protected]
2019-05-14 15:47:28 Yeah it's not letting me post the diagram. Would be much appreciated if you can contact me by email so I can send it to you. My email is [email protected] matt.b
matt.b 