Chapter 3: Configuration
Output Offset
The output offset is the amount by which the output is shifted. Equation 1 shows how the output offset affects the output of the buffer. The negative output rail will clip any reading that has a negative input differential unless the buffer’s output offset is raised. For this purpose, output offsets of 0 V and 2.5 V are individually jumper selectable for each channel on the SDAIBB when mated with a compatible data acquisition model. JP5 corresponds to channel A, JP6 corresponds with channel B, JP7 corresponds with channel C, and JP8 corresponds with channel D.
An output offset of 0 V is always available. See Table 4 for a list of models that support the 2.5 V output offset. An output offset of 0 V is used for positive only differentials, and an output offset of 2.5 V provides the maximum input range for signals that run equally positive and negative.
A different output offset may be brought in on the terminal blocks with the output offset jumper removed on the corresponding channel.
Equation 1: Vout = (IN + − IN − )Gain + OutputOffset
Gain Selection
The gain is individually selectable on each buffer with a two- position jumper. Gains of 1 and 22.28 are conveniently provided on the unit for each buffer. JP1 controls the gain on channel A, JP2 controls B, JP3 controls C, and JP4 controls D. Unity gain is ideal for eliminating the impedance mismatch between input devices and the data acquisition module. Table 5 shows the maximum voltage ranges that can be amplified by the provided gain of 22.28. To change the gain, leave the jumper in the User/22.28 gain position, remove the
SDAIBB1300 Manual | 9 |
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