Hi guys,
I have a signal to drive a servo motor
The signal is a pwm and a direction pin (0 or 3.3v)
The servo driver I have is not compatible and requires a negative voltage to turn counter clockwise and a positive voltage to turn clock wise
If there a way to flip the voltage to negative when the direction pin is enabled ?
Perhaps I could use a simple h bridge and use that to flip the signal ?
Link to servo driver datasheet?
Arduino cannot produce negative voltages, post a link to that controller.
The servo driver is a d200s
Uses the same manual as the d100s
It appears it works with negative voltages when in torque mode
Gadgeroonie:
It appears it works with negative voltages when in torque mode
The schematic shows all input signals are opt-isolated, you statement makes no sense. Are you sure you are using what you linked to?
Paul
Paul_KD7HB:
The schematic shows all input signals are opt-isolated, you statement makes no sense. Are you sure you are using what you linked to?Paul
Er yes
4 inputs are optoisolated the rest are not
Regardless, i am asking how to reverse a signal voltage
Do u have any suggestions ?
Gadgeroonie:
Er yes4 inputs are optoisolated the rest are not
Regardless, i am asking how to reverse a signal voltage
Do u have any suggestions ?
I see the following inputs:
No fourth input on the document.
But to answer your question about reversing a signal voltage, a single transistor will invert the digital signal.
Paul
Gadgeroonie:
Regardless, i am asking how to reverse a signal voltageDo u have any suggestions ?
Ignoring all the other sensible advice you have been given, a simple inverter will turn a digital signal "upside down".
The other piece of advice I can give you is to check your keyboard, as the Y and O keys appear to be intermittent.
Didn't read the document, but an opto could be normally off when connected between pin and ground, and normally on (inverted) when connected between pin and VCC.
Leo..
Gadgeroonie:
Hi guys,I have a signal to drive a servo motor
The signal is a pwm and a direction pin (0 or 3.3v)
The servo driver I have is not compatible and requires a negative voltage to turn counter clockwise and a positive voltage to turn clock wise
Well that's not the case is it - the position mode wiring diagram on page 4 clearly shows a standard
step/direction opto-isolated interface....
Hi,
Have you tried a connection where the direction terminals are either connected to 5V or left open.
-5V is not the case, it is a simple logic HIGH/LOW to give you the two directions.
The terminals are polarised to make sure you activate the opto.
The wires are shown zig-zagged because they represent twist pairs.
It will be interesting to see if 3.3V will be enough.
So forget about -5V needed.
Tom.... 
The diagram in the manual is for position mode
Torque mode uses different pins
Pin 5 is for the torque voltage
‐‐-------------------
What i want to do is flip a 'analogue' voltage to negative
Ie 0.15 volts becomes -0.15 volts when the direction pin is enabled
Gadgeroonie:
What i want to do is flip a 'analogue' voltage to negativeIe 0.15 volts becomes -0.15 volts when the direction pin is enabled
Except that the concept of 0.15V is nonsense in this case. PWM is a digital signal. It stands for Pulse Width Modulation. It moves between logic 0 and logic 1 only.
Except that isnt the case
The voltage is cleaned from a pwm to a smooth analogue voltage using a DAC
Gadgeroonie:
Except that isnt the caseThe voltage is cleaned from a pwm to a smooth analogue voltage using a DAC
Where is this DAC ?
I see nothing in the documentation about needing negative drive voltages. The motor is driven by A/C so it makes no sense to drive anything with a negative value. All the input signals go through opto isolators and will only work with positive signals. I don't understand where pwm comes into this. Please elighten me .
A circuit connection diagram would help.
skyvan:
Where is this DAC ?I see nothing in the documentation about needing negative drive voltages. The motor is driven by A/C so it makes no sense to drive anything with a negative value. All the input signals go through opto isolators and will only work with positive signals. I don't understand where pwm comes into this. Please elighten me .
A circuit connection diagram would help.
Good luck on getting a straight answer. I give up.
Paul
The manufacturer has told me it needs a positve and negative voltage to drive cw and ccw
A dac cleans the signal and makes the operation smooth
‐---------------------------------
My question is how to flip a voltage to negative nothing about the servo driver(posting the manual has just confused the issue, its a rubbish manual tbf)
Gadgeroonie:
The manufacturer has told me it needs a positve and negative voltage to drive cw and ccwA dac cleans the signal and makes the operation smooth
‐---------------------------------
My question is how to flip a voltage to negative nothing about the servo driver(posting the manual has just confused the issue, its a rubbish manual tbf)
If you really are using a DS100S as you indicated and linked to earlier then nothing you have said about the design makes any sense at all ! Nothing at all. You talk of cw and cww but I can't find them at all. You talk of using a DAC but I can't see where it fits into your system especially if you say it needs to provide negative and positive drive.
For anyone to help you you need to provide a scematic of how you think you are going to connect it all together.
Bye
I dont want any help regarding the DS200s
(The servo will work without a DAC but you get a less smooth motion)
Why does everybody want to focus on the servo drive
I asked for suggestions on how to turn a positive analogue signal to negative