ABB模块 型号DSMB-02C输出模块

ABB模块 型号DSMB-02C输出模块

ABB模块 型号DSMB-02C输出模块

系统接地问题的讨论

(1)主机及各分支站以上的部分，其接地应用10mm2的编织铜线汇接在一起经单独引下线接至独立的接地网，一定要与低压接地网分开，以避免干扰。系统接地电阻应小于4Ω。PLC主机及各屏、柜与基础底座间要垫3mm厚橡胶使之绝缘、螺栓也要经过绝缘处理。

(2)I/O站设备本体的接地应用单独的引下线引至共用接地网。

(3)通信电缆屏蔽层应在PLC主机侧I/O处理模块处一起汇集接到系统的专用接地网，在I/O站一侧则不应接地。电缆接头的接地也应通过电缆屏蔽层接至专用接地网。要特别提醒的是决不允许电缆屏蔽层有二点接地形成闭合回路，否则易引起干扰。

(4)电源应采用隔离方式，即电源中性线浮地，当不平衡电流出现时将经电源中性线直接进入系统中性点，而不会经保护接地形成回路，造成对PLC运行和干扰。

(5)I/O模块的接地接至电源中性线上。

ABB模块 型号DSMB-02C输出模块

Discussion of system grounding problems

(1) For the parts above the host and each branch station, the grounding should be connected with 10mm2 braided copper wires through a separate lead line to an independent grounding network, which must be separated from the low-voltage grounding network to avoid interference. The ground resistance of the system must be less than 4 ohms. The PLC host, the screens, cabinets and the base should be insulated with 3mm thick rubber, and the bolts should also be insulated.

(2) The grounding of the device body at the I/O station should be led down to the common grounding network separately.

(3) The communication cable shield layer should be assembled at the I/O processing module on the PLC host side together with the special ground network connected to the system, and the I/O station side should not be connected to the ground. The grounding of the cable connector should also be connected to the dedicated grounding network through the cable shielding layer. In particular, it is necessary to remind that the cable shield layer must not be allowed to have two points of ground to form a closed loop, otherwise it is easy to cause interference.

(4) The power supply should be isolated, that is, the neutral line of the power supply floats, and when the unbalanced current appears, it will directly enter the neutral point of the system through the neutral line of the power supply, and will not form a circuit through the protective grounding, causing the operation and interference to the PLC.

(5) Connect the ground of the I/O module to the neutral line of the power supply.