怎么用34921T测量热电偶

嗨，我有34980A，34921A和34921T。
我很难让温度正确测量，我怀疑这是由于参考。
通过这种安排，我应该设置对INTernal的引用，但该选项确实_not_通过键盘或基于lan的GUI出现。
另一方面，当我选择固定参考时，环境温度显示为约-2C（对我们的实验室来说太冷），并且参考设置为EXTernal，显示为-OVERLOAD。
我仔细检查了布线，看起来都很好。
另外，我尝试了另外一个34921T和其他热电偶，我得到了相同的结果。
更多信息：J型热电偶34980A固件：2.43-2.43-2.07-1.05 34921A固件：1.21谢谢，David编辑：drdroege于2014年2月18日下午4:13根据建议，我使用SCPI命令设置：CONF：TEMP TC
，J，（@）和SENSe：TEMPerature：TRANsducer：TCouple：RJUNction：TYPE INT，（@ 2001）（顺便说一句，使用没有通道的（@）会产生“超出范围”错误;我有热电偶
34921T中的前6个通道）。
但DMM返回的温度仍然不正确（〜-3.2C）。
我使用SCPI命令查询Type以确保它被设置为INT，但由于某种原因，34980A键盘菜单仍然表明它已被修复。
34980中有两个模块，34921A位于插槽2中，我在插槽1中有一个34925A。为了帮助排除故障，我删除了34925A并将34921A / T插入插槽1并且仍然保持相同（
〜2℃温度。
注意：在DMM测量之前，我将关闭热电偶继电器（1001或2001）和总线继电器（1911或2911），具体取决于模块所在的插槽。



     以下为原文

  Hi,
I have a 34980A with a 34921A and 34921T.

I'm having difficulty getting the temperature to measure correctly and I suspect that it's due to the reference.
With this arrangement, I should set the reference to INTernal, but that option does _not_ appear via the keyboard nor via the lan-based GUI.  On the other hand, when I select a reference of Fixed, the ambient temperature is displayed as about -2C (little too cold for our lab), and with the reference is set to EXTernal, the display is -OVERLOAD.
I've double-checked the wiring and all looks good.  In addition, I tried another 34921T with other thermocouples and I get the same result.

More info:
J-Type thermocouples
34980A Firmware: 2.43-2.43-2.07-1.05
34921A Firmware: 1.21

Thanks,
David

Edited by: drdroege on Feb 18, 2014 4:13 PM
As suggested, I used SCPI commands to set:  
CONF:TEMP TC,J,(@)
and
SENSe:TEMPerature:TRANsducer:TCouple:RJUNction:TYPE INT, (@2001)  (btw, using the (@) without a channel gives an 'out-of-range' error; I have thermcouples on the first 6 channels in the 34921T).
but the temperature that the DMM is returning is still not correct (~-3.2C).
I used SCPI commands to query the Type to ensure that it was being set to INT and it was though, for some reason, the 34980A keypad menu still indicates that it is FIXed.
There were two modules in the 34980, the 34921A was in slot 2 and I had a 34925A in slot 1.  To assist in troubleshooting, I've removed the 34925A and inserted the 34921A/T in slot 1 and am still getting the same (~2degC) temperature.

Note: Prior to the DMM measurment, I am closing the thermocouple relay (1001 or 2001) and the bus relay (1911 or 2911) depending on the slot that the module is in.