I have analog output 0-5V from a MCP4725 Digital to Analogue Converter. Can I use this 0-5V as control input to a DC motor driver? All the motor drivers I see talk about PWM digitial input and I am wondering if for instance the TB6612FNG Dual DC Motor Driver could be controlled with an analog 0-5V input also?
The reason is I have 2 hydraulic pumps with a proprietary 0-5V control input which I would like to replicate a control system for. I would love to use PWM since I have a radio control receiver into my Arduino Mega and putting it through the DAC 0-5V output is another layer of complexity already. But I cannot because I need to replicate the original control system as closely as possible I think!
Any input appreciated. I cant help thinking the PWM "duty-cycle" is a replication of analogue voltage and so I should in theory be able to use analog 0-5V input as control with most motor drivers?
What does the datasheet of that driver tell?
Power controll is preferably done by PWM as it's the most effective way.
Can You find some other use of that analog output device? It will surely not power any motor.
I think you are right Railroader PWM is the optimal way to go. The analog output device DAC will not power any motor but can provide the control signal for a motor driver unit (the motor driver unit has a separate power input to drive motors + the 0-5v control logic power input from say Arduino or a DAC).
If I look at the spec of the motor driver I am trying to replicate it seems to accept PWM input also as the analog control input. Which has me wondering if PWM as received by the motor driver is just "received/seen" as a voltage in the same way an analog voltage would be?
I get easily confused with all this analog/digital implications - perhaps because Arduino deals with them quite distinctly, but maybe in the most basic sense both analog 0-5V and PWM 0-5V are seen as 0-5V by the motor driver and so either will do and I am worrying for nothing!?
I might just buy the TB6612FNG Dual DC Motor Driver and experiment but was hoping someone could tell me yes/no;- it reads the PWM control input as say 12Bit 0-4095 levels and then outputs the desired motor voltage. That way I could perhaps deduce that a pure analog 0-5V input would not work. It could be that both methods can be "mapped" and I just do not understand it enough
Cheers
Those motor drivers are pretty basic step & direction input drivers. However, I have a Syren 25 driver that can be controlled a number of ways. One of those is via a 0-5V input. It can be configured so the 0-5V is either unidirectional or 0-2.5V one direction, 2.5 - 5V the other.
No. They are two completely different things. The analog output provides a voltage that vary from 0 to 5V with multiple steps in between. PWM switches between 0 and 5V (nothing in between) and only changes the duty cycle (on/off ratio) of the signal.
Where it may become confusing is because you can filter a PWM signal to produce an analog signal as shown in the diagram you presented above.
That circuit can produce an analog signal, not analog motor power for direct drive of a motor.
If I would build an analog, 0 to 5 volt motor controller I would read the analog signal and scale it to PWM values that then would be sent to a driver.
OK so that brings me full circle to my DAC which is essentially the filter converting PWM to analog V
The screengrab was from the Syren25 datasheet. The Syren25 is what I am trying to imitate with my 'mock-up' bench test system and so I really want an Arduino type (TB6612FNG Dual DC Motor Driver) that can be controlled with analog 0-5V input. BUT! they all seem to specify PWM control.
Exactly. These are the Syren25's I would like to imitate on the bench....the 0-5V analog control comes in from center bottom and the actual motor supply V comes in left and right bottom and into the driver(s) at the top end. The driver output comes out either side of the input there.
So these drivers dont take the PWM control without being filtered to appear as analog. Yourself and Cedarlakeinstruments got me to the point where my DAC can output the 0-5v filtered PWM to the controllers
Now I just need motor drivers that can replicate the Syren 10/25 behaviour and take the 0-5V DAC output.........or as you suggest for the bench test version I might have to convert back to PWM to send to the TB6612FNG Dual DC Motor Driver. This I guess will introduce more error (i.e. going from PWM-DAC-PWM. I may as well just utilise the Arduino 0-5V PWM output! But that does not help me making my bench (radio control) system that could control the Syren25 if needed.
You have a DAC producing 0 - 5 volt, told in the first post. Why not just use that?
Usually the goal of a project is to achive a certain function but haven't we gone out on side tracks discussing intermediate technics?
A logic block diagram showing the start, the middle and the goal could give a better overwiew. Maybe You've got the tips You needed......
You can buy a Syren25 off the shelf. Is this for cost reasons, space, availability? All of the above?
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And consider, that if efficiency isn't a problem, you can use a FET after the 0-5V output to drive a motor. The main issue is that it will dissipate a lot of power and it's harder to do bidirectional motion.
