PU512工控DCS系统备件
当使用5500系列本质安全控制器的NPN（电流吸收器）开路集电极输出时，除电源屏障外，还必须选择负载电源屏障。最大负载供电屏障电阻可通过使用以下公式确定。用户必须提供负载电压降Vload和负载电流Iload（最大20 mA）的值：Rb最大值。Vs-Vload-3.4 Iload，其中：Rb max=最大势垒电阻Vs=电源电压V1oad=负载电压降3.4=输出电路电压降（3.4V）Iload=输出电流（最大20mA）源（PNP）仅输出本质安全齐纳二极管势垒#937ZH-DPCD-2建议用于FM认证和UL认证位置。或者，当5500系列本质安全控制器的PNP（电流源）开路集电极输出时，用户可以选择自己的信号返回屏障。对于非I类1区A和B组危险场所的PNP输出应用，除电源屏障和负载供应屏障外，还必须选择信号屏障。有关参考，请参阅三屏障PNP输出配置的控制图。最大信号返回屏障电阻和最大负载供应屏障电阻之和可使用以下公式确定。用户必须提供负载电压降、Vload和负载电流的值，Iload（最大20 mA）：Rbls+Rbrs=Vs-（Vload+Vbrs+0.4）Iload其中：Rbls=负载供应屏障电阻Rbrs=信号返回屏障电阻Vs=电压供应Vload=负载压降Vbrs=输出开关压降0.4=输出开关电压降（0.4V）Iload=负载电流（最大20mA）适用于I类1区危险场所的PNP输出应用，除电源屏障外，还必须选择A和B组信号返回屏障。有关参考，请参阅两个屏障PNP输出配置的控制图。.
When using the NPN (current sink) open collector output of the Series 5500 Intrinsically Safe controls, a load supply barrier must be selected in addition to the power supply barrier. The maximum load supply barrier resistance can be determined by using the following the formula. The user must provide values for the load voltage drop, Vload, and the load current, Iload (20 mA maximum):Rb maximum. Vs - Vload - 3.4 Iload where: Rb max = Maximum Barrier Resistance Vs = Voltage Supply V1oad = Load Voltage Drop 3.4 = Output Cir. Voltage Drop (3.4V) Iload = Load Current (20mA max.) Signal Return Barrier for Source (PNP) Output Only Intrinsic Safety Zener Diode Barrier #937ZH-DPCD-2 is recommended for FM Approved and UL Listed locations. Alternatively, the user may select his own signal return barrier when the PNP (current source) open collector output of the Series 5500 Intrinsically Safe controls. For PNP output applications in hazardous locations not classified as Class I, Division 1, Groups A and B, signal barrier must be selected in addition to the power supply barrier and the load supply barrier. For reference, see Control Drawing for the three barrier PNP output configurations. The sum of the maximum signal return barrier resistance and the maximum load supply barrier resistance can be determined using the following the formula. The user must provide values for the load voltage drop, Vload, and the load current, Iload (20 mA max): Rbls + Rbrs = Vs - (Vload + Vbrs + 0.4) Iload where: Rbls = Load Supply Barrier Resistance Rbrs = Signal Return Barrier Resistance Vs = Voltage Supply Vload = Load Voltage Drop Vbrs = Signal Return Barrier Voltage Drop 0.4 = Output Switch Voltage Drop (0.4V) Iload = Load Current (20mA max.) For PNP output applications in hazardous locations classified as Class I, Division 1, Groups A and B, signal return barrier must be selected in addition to the power supply barrier. For reference, see Control Drawing for the two barrier PNP output configurations.
