High Speed Thermocouple Readings I'm currently attempting to take readings from 10 thermocouples using an Arduino Mega. I've been using MAX31850 1Wire Thermocouple Modules (with the Adafruit breakout) to perform the readings, but their response time has been very slow (~500ms each). I'm not sure if most of this latency is coming from the IC, or from the communications protocol, or perhaps even the DallasTemperature library.

For my application, I need to be able to read all 10 thermocouples in at most 250 ms (and faster would be better) and so I can afford up to 25ms per thermocouple. I would also like to be measuring with a precision of about 1-2 F.

I assume I will probably have to use a different amplifier, and I've seen recommendations online of using an external ADC to achieve higher speeds, which I would be happy to do, but I don't understand why that would make a substantial difference on speed since the onboard ADC can already sample at about 1/10 ms. 

I would greatly appreciate any recommendations on how to achieve these speeds.
1-wire transmission takes ~100us/1bit so 1ms/byte. so unless the adc is that slow, it shouldn't take you anywhere close to 500ms to take 1 reading, even if you factor in the overhead / reset.

there are dedicated chips but as you mentioned putting an amplifier (instrumentation amps for example) isn't that difficult. simpler with chips with built-in PGA + differential adc. My favorite here are some of the AVR chips (ATtiny85 or ATmega32U for example). But lots of Freescale / STM32F3 chips also work, so long as you are willing to dive into their and roll your own. Lots of fun.