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Project objective

Make a simple data logger with up to 8 digital inputs, 4 to 8 analog inputs. Additionally, it should have several digital and analog outputs. A/D converter should be of 16-bit resolution or higher in order to be able to measure small signals such as those from TC probes.

Perhaps this module could be "modular" itself: i.e. that it can accept AFE for various purposes. The AFE module could be a piggybacked on the main PCB. Piggyback contains input/output protections, gain attenuation, buffering A/D, D/A while on main PCB reside power supply, DIB communication, MCU/FPGA and memory buffer.

Possible piggyback modules:

• 8- or 16-ch thermocouple inputs
• 8- or 16-ch bipolar analog inputs
• 8-ch isolated unipolar or bipolar analog inputs
• 8 or 16 digital inputs
• 2 x voltage monitor + 2 x dual-range current monitor non-isolated groups
• 2 x voltage monitor + 2 x dual-range current monitor isolated groups (1 x voltage, 1 x dual-range current)

Separation of AFE and DBE (digital back-end) will make possible isolation in-between inputs and outputs.

Module front panel has limited area to mount connectors. If AFE piggyback modules are used that offer possibility to mount connectors on two level. Another possibility is to use 2-level connectors with 3.5 mm (check WE-online offering).

Additionally some piggyback modules can bring functionality that goes beyond data logging. For example:

• 2-, 4- or 8-ch analog outputs
• high precision current source and/or voltage reference
• switch matrix (e.g. 4 x 4, 4 x 8)
• 4 or 8 power relays or solid state switches
• 8 or 16 signal relays (if it makes sense at all)