几个仪表题.? 1 field bus,连有5台仪表 ,用hart 如何连接? 串入要通讯的仪表回路中 并入要通讯的仪表端子,必须红接正,黑接负。 并入任一个仪表端子,没有极性要求。 并入供电电源 2 what is the greatest limitation for a buff to calibrate aph-tester? 用于校正ph计的缓冲液有什么 局限性/不利点 ? reliability 可靠性 accurate 精确度 respose time 反应时间 drift 漂移 3 how to stop cycling of valve?( 题意或许是指,阀门动作太频繁?) increase setpoint 提高设定值 decrease setpoint 减小设定值 increase dead band 增大死区 decrease dead band 减小死区 4 when install something,how to 保证密封性/可靠性/正确方法?比如swagelok 接头 ,fitting 用手拧不动后再forwardtighten 1/4 cycle --------------------------------------- 1-1/4 是1/4圈还是1-1/4圈 ??/?? 5 whenthe vapor pressure instrument is moved from lower temperature environment to ahigher temperature environment, what will happen on the liquid in theinstrument? 当蒸汽压力仪表从低温环境到高温环境,仪表内的液体会有什么变化? liquid from bulb to capilliary 液体从温泡流向毛管 liquid from capilliary to bulb 液体从毛管流向 温泡 vapor pressure non stable. 蒸汽压力不稳定 indicate not correct 指示错误 6 dcs shut down, 给卡板做清洁的内容? 用中性液清洗 用 fine 清洗液 加注润滑油 吸尘器 7 用卫星天线的scada系统,如何检查卫星天线信号的sensitivity / 灵敏度? power down, connect an ohm-meter, power u, check signal sensitivity power down, connect in a signal strength meter,power up, check signal strength. microhmmeter 还是 ohmmeter ??????????????????? ohm meter, turn off power ,test sensitivity turn off power, connect wire ,test sensitivity micrometer ,connect wire , test sensitivity ampmeter, turn of power ,test sensitivity 8 analyzer for methane, 处于高浓度的methane 较长时间,将发生什么?或有什么影响? sensor 的灵敏度将降低 对 analyzer 无影响 9 一个气阀 5-10 psi,positioner can accept 3-10psi signal, where will it startfrom? 气阀范围 5-10 psi ,定位器 范围 3-10 psi ,阀门在多大压力时动作? startat 3 psi start at 5 psi 10 valve:3-15psi, positioner 5-20psi, when it start to work? 气阀范围 3-15 psi ,定位器 范围 5-20 psi ,阀门在多大压力时动作? 3 psi 5 15 20 请各大侠帮忙看看,多谢。 查看更多