I'm using an encoder, a load cell and a low speed DC motor in my project for a torsion testing machine. The encoder is separate from the motor and serves to measure angle rather than angular velocity.
I am wondering if the myDAQ is the interface to use for controlling the motor, and reading the load cell + encoder simultaneously (through LabView) - and if there is a need for any additional hardware for interfacing, as I already have an amplifier for the load cell.
Thanks in advance.
The myDAQ has 2 analogue in and out so that's fine for your Load Cell and DC motor. Remembering that the myDAQ has no signal conditioning, but you did say you have an amplifier for your load cell so that should be OK. Also something to bear in mind is how much current your DC motor is going to draw as the myDAQ can only provide 2mA from the Analogue Out.(As seen in the User Guide and Spec). Without knowing more about your motor, it is difficult to say whether this will be enough. If you needed more you could build sort of amplifier in circuitry and use the myDAQ built in Power Supply, this being limited to 500mW.
It also has 8 digital in lines, 1 of which you need for your encoder, however, these have to be software timed so that may be a problem in your application? How fast does the encoder data arrive?
I hope this is of some help and let me know if you have any more questions or need something clarifying.
The encoder is expected to work on 500 pulses out (per revolution). This may go up to 1000 if another model is selected. I don't think that software timing is a problem since the angular displacement is the parameter we're after, rather than velocity.
I read through the myDAQ guide and it seems that it can not be used for this particular motor, seeing as the DC motor works on a 24 V supply, at 15 W. The motor will probably be controlled externally as opposed to it being done on a PC interface. However the load cell and encoder both need some kind of peripheral (as cost effective as possible) in order to be connected to LabView and for now it seems that the myDAQ is the best solution.
Thanks for the reply, I might come up with another query soon....
I realise that you will probably use the onboard counter to interface with the encoder which will be ideal.
Good luck with your application.