Instrument Circuitry – Reference 3000 Schematic/Block Diagrams
25
Figure 3-7
One AE Channel
Notes for Figure 3-7:
One of eight identical channels is shown.
The input buffers work over the entire Reference 3000 compliance voltage range.
The maximum useable differential voltage between the two inputs on a channel is
5 V.
Each channel has its own filtering. The Aux A/D Channel filter is not useful for switched inputs.
The ×10 and ×100 gains in the Aux A/D channel can be used to improve A/D resolution.
The inputs have an input impedance of greater than 10
11
Ω as long as the product is powered.
The inputs will not be damaged by connection to voltages as large as
36 V versus the Reference
3000’s ground, regardless of the compliance-voltage setting. This is true even when the Reference
3000 is not powered up. They cannot measure voltages larger than the compliance voltage.
