PEPPERL+FUCHS隔离栅，PZM58N-S32AGROBN-1213
在设计电阻温度计3 -
4线连接，这是必要的，以确保供应
电缆敷设的测量电阻器，这是不
情况下，所有的温度计。往往是由连接
在这种结构中的连接头。这，
再次产生问题的，导线的电阻和
随温度变化的影响s以上的长度的
实际温度计。由于比较小
连接头之间的距离和测量
电阻，这些错误是远远小于与2线连接。
如果一个电导体的温度下在
Continuous correction of the line resistance during
measurement is not possible. That is why the supply cables
should not be longer than about 100 m (109.36 yd) in the
case of the 2-wire connection. The resistance of a 1 m
(1.09 yd) long copper cable with a cross section of 1 mm2 is
approx. 0.017 Ω. Consequently, in this case, a wire resistance
of about 1.7 Ω is likely. Changes to resistance due to the
infl uence of temperature are included in the result. If the
cable lengths are greater, so that higher wire resistances are
unavoidable, you should use 3- or 4-wire connections.
3-Wire Connection
In order to measure the line resistance RL and its changes,
a third wire is laid directly to the connector point at the
measurement resistor. The wire resistance of this line has no
infl uence on measurement because the supply current does
not pass through it. Thus, the voltage is measured directly on
the measurement resistor.
梯度，电子流内发生
导体，造成电动势
（EMC）的温度成比例
渐变。的量和方向，这
电动势依赖于温度的大小
梯度和导体材料上
（图38） 。两个自由端之间测得的电压
导体产生的电压差异，取决于
的温度差异和热电
导体的特性。这种现象，被称为
塞贝克效应，由TJ塞贝克发现