FieldPoint Family
Program labveiw to read torque
Hi Bruce,
The AO-210 will source 1mA without and 10mA with an external power supply (page 1). The SG-140 requires a minimum bridge resistance of 477Ω at 10V of excitation (page 7). You should check with Futek for the maximum current the device will draw at 10V of excitation. If it's greater than 10mA for the AO-210, or 21mA for the SG-140, you cannot excite the sensor directly from FieldPoint module. This is not a big problem. In fact, it points to a better solution altogether.
If you excite the sensor with an external power supply (link a standard 120VAC - 10VDC converter), you could measure both the sensor output and the excitation voltage with the AI-110. The computed torque would then be a function of two real-world measurements, not a real-world measurement and a software setting. I'll assume that, "Now, the numbers i am getting from the AO-110, what do they represent?" is a typo, and that you're asking what the numbers from the AI-110 are. As long as you have not applied any scaling to the AI-110 channel in Measurement and Automation Explorer (MAX), these numbers are voltage readings in units of volts. Please see the previous post on how to compute the scaling from volts to torque in the LabVIEW program.
If you like, you can linearly scale the voltage data on a FieldPoint channel. In MAX >> My System >> Data Neighborhood >> FieldPoint Items >> <Controller Name> >> AI-110 >> Channel n >> Scales. You can specify a slope, a y-intercept, and scaled units. The units in LabVIEW for such a channel would be whatever you set in MAX.
Message Edited by Pie56694 on 07-02-2008 02:19 PM
The AO-210 will source 1mA without and 10mA with an external power supply (page 1). The SG-140 requires a minimum bridge resistance of 477Ω at 10V of excitation (page 7). You should check with Futek for the maximum current the device will draw at 10V of excitation. If it's greater than 10mA for the AO-210, or 21mA for the SG-140, you cannot excite the sensor directly from FieldPoint module. This is not a big problem. In fact, it points to a better solution altogether.
If you excite the sensor with an external power supply (link a standard 120VAC - 10VDC converter), you could measure both the sensor output and the excitation voltage with the AI-110. The computed torque would then be a function of two real-world measurements, not a real-world measurement and a software setting. I'll assume that, "Now, the numbers i am getting from the AO-110, what do they represent?" is a typo, and that you're asking what the numbers from the AI-110 are. As long as you have not applied any scaling to the AI-110 channel in Measurement and Automation Explorer (MAX), these numbers are voltage readings in units of volts. Please see the previous post on how to compute the scaling from volts to torque in the LabVIEW program.
If you like, you can linearly scale the voltage data on a FieldPoint channel. In MAX >> My System >> Data Neighborhood >> FieldPoint Items >> <Controller Name> >> AI-110 >> Channel n >> Scales. You can specify a slope, a y-intercept, and scaled units. The units in LabVIEW for such a channel would be whatever you set in MAX.
Message Edited by Pie56694 on 07-02-2008 02:19 PM
