Understanding FieldDAQ Power Consumption Compared to cDAQ

Issue Details

Why does FieldDAQ consume more power than cDAQ?

Solution

FieldDAQ devices typically consume more power than cDAQ systems because they integrate both the DAQ backend and I/O modules into a single ruggedized unit. Conceptually, a FieldDAQ can be thought of as equivalent to a cDAQ chassis plus two c-series modules. This integration results in higher overall power consumption, though not drastically so.

One key example is the FD-11637, which includes high-power excitation circuitry internally. In contrast, a comparable c-series module like the NI-9237 requires an external power supply to deliver similar excitation power. This built-in capability contributes to the higher power draw of FieldDAQ units.

Additional Information

Example: Power Consumption Calculation for FD-11637
FD-11637’s power consumption can be broken down into two main categories:

1. Static Power (Always-On)
Typical: 5.5 W
Maximum: 7.5 W

2. Variable Power (Sensor Excitation)
Example configuration: 8 channels configured for 10 V excitation into 350 Ω full bridges
Power per channel: 10^2 / 350 = 286 mW
Total excitation power: 8 × 286 mW / 0.5 ≈ 4.57 W
Total max power consumption: 7.5 W + 4.57 W ≈ 12.1 W