ayumisano Posted August 21, 2005 Report Share Posted August 21, 2005 Dear all, Is it possible to make PCI-6534 to read the input which is around 200mV? I read the datasheet which is available on ni.com and it says that PCI-6534 is 5V TTL. Does it mean that there is no way for it to trigger a reading as long as the voltage is smaller than 5V? Thank you very much for your attention!! Ayumi Quote Link to comment
m3nth Posted August 22, 2005 Report Share Posted August 22, 2005 Dear all,Is it possible to make PCI-6534 to read the input which is around 200mV? I read the datasheet which is available on ni.com and it says that PCI-6534 is 5V TTL. Does it mean that there is no way for it to trigger a reading as long as the voltage is smaller than 5V? Thank you very much for your attention!! Ayumi 5745[/snapback] Well since the TTL specification says that a '0' is anything < 0.5V and a '1' is anything > 2.5V, the most straightforward answer is no, you can't trigger a 5V TTL signal with only 200mV. There is most likely a workaround however. Does the 200mV incoming signal meet some kind of spec? What about using a standard RS422/485->RS232 converter? Those use a voltage differential to determine a '0' or '1' where everything between -200mV to 200mV is no man's land, but maybe you could rig a workaround. If you have the abililty to use other hardware it probably won't be a problem to find a workaround, but by itself, I don't think you'll be able to tirgger the PCI-6534 directly. Quote Link to comment
Neville D Posted August 22, 2005 Report Share Posted August 22, 2005 Dear all,Is it possible to make PCI-6534 to read the input which is around 200mV? I read the datasheet which is available on ni.com and it says that PCI-6534 is 5V TTL. Does it mean that there is no way for it to trigger a reading as long as the voltage is smaller than 5V? Thank you very much for your attention!! Ayumi 5745[/snapback] You could continuously read the input and discard data that doesn't fall within your criteria (200mV or whatever). Neville. Quote Link to comment
m3nth Posted August 22, 2005 Report Share Posted August 22, 2005 You could continuously read the input and discard data that doesn't fall within your criteria (200mV or whatever).Neville. 5771[/snapback] TTL is digital, not analog... you can't check voltages in between unless you're doing an analog acquisition. Quote Link to comment
AnalogKid2DigitalMan Posted August 22, 2005 Report Share Posted August 22, 2005 You could wire up a comparator chip to output TTL logic levels based on a 200mV threshold. Quote Link to comment
ayumisano Posted August 28, 2005 Author Report Share Posted August 28, 2005 You could wire up a comparator chip to output TTL logic levels based on a 200mV threshold. 5778[/snapback] Dear all, Thank you very much for your help Ayumi Quote Link to comment
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