Ok MathewW, you make this sound simple, but I'm having issues with it as well. Here is my example...
I have a 6255 with a T-type thermocouple.
From what I know, this T-type thermocouple measures from -270 °C to 400 °C
The voltage output of T-type over this range is -6.25mV to 20.87mV or ~ 40.47uV / °C
The 6255 supports gain ranges of ±10 V, ±5 V, ±2 V, ±1 V,±0.5 V, ±0.2 V, ±0.1 V so obviously I want the 100mV range
I'm using the SCB-68 with built in CJC
Have the board setup for differential channels so a 100k ohm bias resistor was added to the channels
In MAX I created a virtual channel for a T-type thermocouple, °C, built in CJC and signal input range 0-100°C.
When I stick a thermocouple on the channel, I appear to get room temperature readings around 30 °C. But I plan on measuring above 100 °C so I changed the scale to 0-200 °C. With the numbers stated above I am still well within the 100mV measurement range so my gain should have been left the same. Now when I run the test panel I get values of 60 °C for the same thermocouple wire sitting in the same room. And I would have thought that my input really should have been ±2470 °C (±100mV / 40.47uV / °C) Can someone please better explain how the "signal input range" works for thermocouple channels in MAX? Is it just smoke and mirrors and you should always leave your thermocouple signal input range at 0-100 - even if you plan on reading 200°C?
