Setting the gain of an instrumentation amplifier to 1

[AQUAMAN]

In a lot of instrumentation amplifiers it seems difficult to get the gain to equal 1 unless you have a 1Meg resistor for the gain setting, and even then its always 1.05 or something.
I would like to use an instrumentation amplifier with a gain of 1.

In the AD8429 datasheet, http://www.analog.com/media/en/technical-documentation/data-sheets/AD8429.pdf, it claims that by not using a gain setting resistor, that the gain will default to 1.
"The AD8429 defaults to G = 1 when no gain resistor is used.
Add the tolerance and gain drift of the RG resistor to the
specifications of the AD8429 to determine the total gain accuracy
of the system. When the gain resistor is not used, gain
error and gain drift are minimal."

Has anyone any experience of this? I presume it means to leave both the terminals for the gain resistor floating.

[tron9000]

well page 15 shows that:

G= 1+ (6k/R_g)

so if R_g is O/C (infinite) then G >> 1. or near as damn it.

why is it vital that you get exactly 1 (0dB)?

[AQUAMAN]

well page 15 shows that:

G= 1+ (6k/R_g)

so if R_g is O/C (infinite) then G >> 1. or near as damn it.

why is it vital that you get exactly 1 (0dB)?

I want it at 1 because its calculating power loss across a transistor

[tszaboo]

Yes, you can just leave it "floating". Though it is not really floating, becuase it is driven internally through a resistor. This is also probably the most accurate way to do A+B-C calculation for analog voltages.