SPice10209 - Type K thermocouple interface

This product is discontinued. It has been replace by the SX10500 Xwire peripheral board

The SPice10209 is an add-on board that provides a SPLat controller with one or two channels of K-type thermocouple input. It uses the Maxim MAX6675 chip to digitize the thermocouple reading. The MAX6675 data is in the "File Resources" area of our resources CD (after October 2004) and also available online. The measurement attributes, including accuracy, are governed by that chip. The salient features are:

• Works with K-type thermocouples;
• Temperature range 0°C to 1024°C is 0.25°C steps (resolution);
• built in cold-junction compensation;
• Accuracy depends on temperature - see chip data.

On the SPice10209 one or two MAX6675 chips are interfaced to the SPLat controller via a TSP (Tiny Serial Peripheral) interface. A dedicated processor provides the interface function.

The MAX6675 takes a fresh temperature reading every 250mS. The SPice10209 processor chip provides flags that allow you to detect when a new reading is available. This can help you avoid processing the same reading more than once (which may or may not be significant, depending on how busy or sophisticated your program is). The flags are available either as simple digital inputs via the SPice pins, or as bit variables via the TSP interface.

There is also an error flag for each channel. This indicates an open thermocouple input, or in the case of the single channel version, an absent channel. The two error flags are available as individual bit variables (via TSP) or multiplexed into a single SPice pin. In the latter case the SPice pins will indicate the flag for the channel which was last read out.

The onboard processor also provides the service of optionally low pass filtering readings to reduce noise. The filter time constant can be set between 0.5S and 4S.

To make the most of your SPice10209 temperature measurements you should read up on thermocouple theory and precautions for their use.

Note: This is a TSP (Tiny Serial Peripheral). It is compatible only with selected SPLat Controllers. Please check the controller documentation to see if it is TSP compatible. That may mean checking its Firmware revision history against the firmware you have in your board(s).