Hello, I have a NI USB-6210 and am trying to use it to start and stop a motor which has the following pins that I would connect to the USB-6210 as shown below (USB-6210 pinout) TTL input to start (0-1V = 0, 3.5-24V = 1) --> connect to pin 6 = PFI 4/P1.0 (Out) TTL input to stop (0-1V = 0, 3.5-24V = 1) --> connect to pin 7 = PFI 5/P1.1 (Out) GND (inputs) --> connect to pin 11 = D GND The digital outputs of the USB-6210 are sourcing outputs (line driver). According to https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MXOSA2&l=de-AT a line driver is defined as: "A line driver is a sourcing output. When in the on state, a line driver will supply Vcc. In the off state, a line driver will float. Because of this, a sinking input is required for proper operation. Please refer to the table below for a simple example of a line driver." The figure at the bottom of the article shows a wiring diagram of the line driver where a resistor is shown between Vcc and Input. I assume this is the 47kΩ pull-down resistor that is mentioned in the USB-6210 specifications which ensures well-defined logical low when LabVIEW would send "false" to the output. However, there is no pull-up resistor to ensure well-defined logical high - do I need to add a pull-up resistor between D GND (pin 11) and the GND input of the motor? According to the USB-6210 specifications the following digital output characteristics are defined: Parameter Voltage Level Current Level VOL 0.6 V 6 mA VOH 2.7 V -16 mA VOH 3.8 V -6 mA To test my LabVIEW program I have connected a voltmeter to pins 6 (PFI 4/P1.0 (Out)) and 11 (D GND). Running the VI and switching to "false" shows 0.0V at the voltmeter (this makes sense because of the pull-down resistor mentioned above, right?). But when I switch to "true" the voltmeter shows around 4.7V where I would have expected a value between 2.7V and 3.8V as shown in the table above. As mentioned at the beginning, the motor needs at least 3.5V to detect the input as logical high - so 4.7V are preferred anyway, but I'd like to understand where those 4.7V come from. Any help is appreciated. Thank you.

LabVIEW

It would really help to see the specs on the motor controller. Or we will continue to engineer ambitiously

"Should be" isn't "Is" -Jay

Message 11 of 11

(233 Views)