DC motor Tach recomendation

15 years 9 months ago #3197430 by JR
DC motor Tach recomendation was created by JR
The literature states that a good DC motor can be used as a DC Tach Generator for speed control. Can you recomend a vendor and or model that has worked well with your controller.

Thank You

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15 years 9 months ago #3198119 by cosma
Replied by cosma on topic Re:DC motor Tach recomendation
Example of top quality motors are the Maxon motors <A href=" www.maxonmotor.com " target=_blank> www.maxonmotor.com .Lesser quality motor will be OK as well.

However, now that Optical Encoders can be added to the AX2550 we recommed that Optical Encoder feedback be used instead.

Tachometers require potentiometers for trimming which some customers have had problem drifting over time.

Optical Encoders are 100% digital device which will ensure stable repetitive behavior. They are also typically easier to mount on an existing motor.

See <A href=" www.usdigital.com " target=_blank> www.usdigital.com for example products.

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15 years 9 months ago #3198796 by JR
Replied by JR on topic Re:DC motor Tach recomendation
Our application is cost sensitive and therefore to add the additional $1xx.00 for the encoder input plus the cost of the encoder would probably exceed the cost of just a DC motor for the input.

Also we are using a potentiometer as the input for steering/positioning.

If we added the encoder input option, would we still have available
the original two(2) analog inputs ?......
or to put it another way ..
would we then have two(2) encoder inputs and two(2)analog inputs ?

Thank You

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15 years 9 months ago #3202511 by cosma
Replied by cosma on topic Re:DC motor Tach recomendation
You cannot use a potentiometer for command AND a tachometer for feedback. As you have seen, there is only one analog input per channel and it can only be used for one or the other.

Encoders may be used for speed feedback in Speed Mode.

In Position Mode, Encoders may also be used but you need to take into account that the Encoder module will report the Encoder's relative position compared to where it was when the controller was powered up.

If you want a sensor that will give you an absolute position, then you should use a pot but you will not be able to send commands via the analog port. Instead you should send commands via RS 232, or use a joystick that outputs of variabe pulse width.


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