The control circuit is a self-balancing current loop which makes use of a four-terminalresistor of nickel wire to assure a close-loop both electrically and thermally.
控温电路采用四端电阻自平衡电流环路，从而保证其电气和温度均处于闭环状态。
2
The main facts we should consider are the trouble caused by the communication cable, communication power, t type branch or the terminalresistor problem in the application of site bus technology.
现场总线在应用中主要考虑其通信电缆、通信电源故障，“T”型分支或终端电阻故障也会引起总线故障。
3
Terminal resistance method: to improve the quality of the communication on the 485 + and 485 - of the last 485 devices with a termination resistor of 120 ohms.