I want to multiplex a 8X8 thermal sensor array using the LTC 2984 demo board.Please tell how i should go ahead?
The LTC2984 provides buffered inputs so you may be able to use an analog multiplexer to increase the effective number of input channels. Your microcontroller will need to configure the mux before beginning a conversion. Use a low-leakage analog mux with low on-resistance to reduce offsets. ADG714 / 715 may be useful.
If you need to use a custom sensor configuration you can use the same memory address for all sensors of that type, this will save RAM and EEPROM space.
Note that due to the power line rejection filtering in the LTC2984 the conversion time per channel will be at least 150ms - this may be an issue if you want to do imaging for example. Just something to be aware of.
Thanks for your reply, i am using a 16 channel analog multiplexer. I have implemented a system wherein i have made 2 columns , 1 column of 3 thermistor and other column of one thermistor. When i am selecting a columns through the multiplexer, i am not able to get proper reading. I am sending the sense resistor current through the signal input to the 16 output lines. I am attaching a picture of the demo software result for your reference. According to me i should get 27 deg c approx when i am selecting output line 1 through select line of mux.
I have to implement a 8 X 8 thermal array (64 sensors), and i want to utilize the on board multiplexer of LTC 2984 demo board for switching between the columns of the array. How should i go ahead if i don't want to use any external multiplexer or maybe one multiplexer at maximum.
The internal multiplexer of the LTC2984 is not user-addressable. It is configured by the part for a specific sensor configuration.
Looks like you are sharing current somewhere, the thermistor appears as 5k instead of the 10k you expect. This would be consistent with two 10k's in parallel.
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