The NL143 Difference Amplifier allows the difference between two signals to be continuously monitored during the course of an experiment.
The module has four inputs and three outputs, allowing three alternative "differences" to be recorded simultaneously from each module. Internal settings define the channels to be subtracted. The module also features a post-subtraction offset control which allows the output to be offset to a desired level e.g. for zeroing at the start of an experiment. While this module was originally designed to allow the differences between two biological parameters to be continuously monitored, it could also be used to remove unwanted offsets introduced into analogue signals originating from computer DAC interface cards.