NI DAQ Range

[tronoh]

Dear Sir

I am using NI PCI 6281 which has analog input range of -10 v to 10 v. My signal has 10.2 V AC, can I connect this with DAQ card safely or it will damage the port?

Waiting for prompt reply.

Kind Regards

Muhammad Irfan

[GerdW]

Hi Muhammad,

read the specifications: it allows at max ±11V against AIGND in working operation. The inputs are protected with ±15V/±25V depending on device off/on state!

[tronoh]

Dear Sir

The signal is in differential mode (i.e two wires one + and other -). No GND being used in the connection scheme. So should I go for connections or not?

Kind Regards

Muhammad Irfan

[crossrulz]

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tronoh wrote:

The signal is in differential mode (i.e two wires one + and other -). No GND being used in the connection scheme. So should I go for connections or not?

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Are those signals referenced to ground somehow?  Even in differential mode, each input should not go beyond the +-11V to ground.

You might want to give this white paper a read:Field Wiring and Noise Considerations for Analog Signals

[JÞB]

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@crossrulz wrote:

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tronoh wrote:

The signal is in differential mode (i.e two wires one + and other -). No GND being used in the connection scheme. So should I go for connections or not?

---

Are those signals referenced to ground somehow?  Even in differential mode, each input should not go beyond the +-11V to ground.

You might want to give this white paper a read:Field Wiring and Noise Considerations for Analog Signals

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At this point we have no way to judge if the signal you are attempting to connect will damage the system.

Let's use some examples and discuss the real use of that third or fourth wire on your primary power cord.

Assumtions:  Something in your system is tied to a publically available power grid ( or, You may be on this planet "Earth", interplanataray travellers are refered to their respective species representatives for advisement)

there are exactly 2 options:

• the system you are testing and the system you are testing with share a common connection to "Earth Ground"
• One or more of those systems is isolated from "Earth Ground" by some manner that has a maximum breakdown potential

Attaching the two systems together will provide a common point of reference between the two of no greater than 20Volts before damage will occur to the DAQ device and potentially the computer housing it.