The RTD-116A is a 16-channel, DSP-based RTD conditioning card for use in Curtiss-Wright’s EDAU-20xx, CDAU-20xx or WDAU- 20xx series products. Multiplexed constant current excitation is provided to reduce sensor self-heating and total power dissipation of the system. The constant current value is software programmable to 0.512, 1.024, 2.048, and 4.096 mA. 

Both 2-wire and more accurate, 3-wire RTD measurements are supported for Platinum RTDs having a 0°C resistance of up to 1,000 Ohms. Linearized output proportional to the measured temperature is provided for most common RTD types including the American (alpha = 0.00392) and European (alpha = 0.00385) curves. Other RTD types may be used without linearization support providing an output proportional to the input resistance. 

The interface is configured to allow for sensor wire resistance compensation when used in the 3-wire mode. No external reference resistors are required. The RTD-116A-1 automatically programs channel gain and offset to allow the user to “zoom in” on a particular temperature (or resistance) range. The module provides continuous gain and parasitic offset error correction and offers an accuracy of ±0.25 percent over the operating temperature range. 

Programmable digital moving average filters provide a choice of channel filtering options. Each channel is sampled at a fixed rate of 312.5 SPS per channel and the result is stored in a Current Value Table at 16-bit resolution. The system can sample this data at any rate.