I am assigned to build a temperature data logger that
[1]can measure from 0 up to 350 celsius,
[2]able to accept both J and K thermocouple,
[3]have at least 20 temp sensors channels,
[4]switching between j and k are provided by software control
[5] necessary to provide cold junction compensation
Am thinking of using AD594 for J and 595 for k TC. or is there any amp that can be used for both J and k? and according to data sheet the AD595/594 are desinged to be used from 0 to 50 deg c. does it mean, i cant use it if i would like to measure up to 350 deg c?
and according to data sheet the AD595/594 are desinged to be used from 0 to 50 deg c. does it mean, i cant use it if i would like to measure up to 350 deg c?
any suggestion on what op amp to use then? but normally, op amp cant really take up too high temperature rite? i wonder what does those commercialized data logger use to amplify their signal.
Sorry, I didn't read your situation properly, I've now realised I don't know enough about your application or the devices to be able to comment on their suitability. If it's a part which doesn't need to be exposed to the temperature you need to measure with the probe, then perhaps it could be kept within its acceptable range simply through careful insulation.
The flow of information would be:
32 input channels -> AD594 and 595 -> multiplexer (i thought of using DG407) -> ATMEGA8 (with ADC) -> SD memory
however, i dont really know how the data logger will be able to identify what type of thermocouple is plugged into it and determine whether to send the signal to 595 or 594.
and im wondering do i use a multiplexer /switch for the connection between input channel and AD595 / 594
The flow of information would be:
32 input channels -> AD594 and 595 -> multiplexer (i thought of using DG407) -> ATMEGA8 (with ADC) -> SD memory
however, i dont really know how the data logger will be able to identify what type of thermocouple is plugged into it and determine whether to send the signal to 595 or 594.
and im wondering do i use a multiplexer /switch for the connection between input channel and AD595 / 594