SB-RIO 9631 Safety regarding question

[Javi_Rome]

Hi folks,

we have a SB-RIO 9631 target that we are going to use for controlling a Quanser Inverted Pendulum model we also have in the lab. My question is if would be safe for the target to connect directly one analog output of the SB-RIO to a amplifier module (also Quanser made, the UPM-1503 version) in order to amplify the control signal and then feed it to a DC motor.

I guess it will be, but since it is not a conventional wiring, I thought I could ask for your impressions. The goal is to control the DC motor and thus the position of the chart/pendulum over the rail. The motor has a frecuency limitation of 50 Hz for safety reasons too, so I am going to implement a low-pass filter in LV before the output of my application.

Best regards, Javi.

[JesusG]

Hi, Javi-R,

there's no problem at all in connecting an external amplifier to a sbRIO AO. It would be safe for the target besides it is a common practice to modify the voltage supplied by the target.

Saludos!

Jesús.

[Javi_Rome]

Hi Jesús,

Thanks for your answer!

In order to prevent a motor failure, I have to implement a 50Hz low pass filter which will prevent higher frecuencies going into the motor, and also

a +/- 5 Volt saturation. In the specifications document it says that you should take care and not to feed the motor with signals more than +/- 15 Volt

3 A peak, and 1 A continuous.

I think I have the voltage constraint covered by the saturation block, but anyone knows how to implement a current limiter?

[JesusG]

Hi, Javi-R,

you can implement a current limiter for your motor just copying the examples you can find on the Internet. Here you are a couple of them:

http://www.vidisonic.com/2008/07/10/current-limiting-circuit/

http://www.radio-electronics.com/info/circuits/transistor_current_limiter/transistor_current_limiter...

Just read your motor specs and choose that one that fits best.

Saludos!

Jesús

[Javi_Rome]

Oh sorry... I mean how to implement it in Labview. The amplifier already has direct connexion to the motor, so I see no way to put a circuit in between.

I attach an amplifier user manual in orders you guys see it.

[Javi_Rome]

I just realize that maybe I could implement the limiter in Multisim and the export it as a Labview Block....

[JesusG]

Yes, you can try. I hope it works!