UFC719AE101 3BHB003041R0101 3BHB00072R0101

On site control unit
The on-site control unit is generally located far away from the control center and installed near the site. Its highly modular structure can be configured into process control units ranging in size from several monitoring points to hundreds of monitoring points according to the needs of process monitoring and control.
The structure of the on-site control unit is composed of many functionally dispersed plug-in boards (or cards) installed in a plug-in box in a certain logical or physical order. Each on-site control unit and its connection with the control management level are connected by a bus to achieve information exchange.
The hardware configuration of the on-site control unit needs to complete the following tasks:
The configuration of plugins is based on the system’s requirements and control scale to configure hardware devices such as host plugins (CPU plugins), power plugins, I/O plugins, communication plugins, etc;
Hardware redundancy configuration is an important means to improve the reliability of DCS by configuring key equipment redundantly. DCS can usually achieve redundant configuration for host plugins, power plugins, communication plugins, network, and critical I/O plugins.
There are corresponding regulations on the logical or physical order of installing various plugins in the plugin box for different DCS hardware installations. In addition, on-site control units are usually divided into two types: basic type and expansion type. The basic type refers to various plugins installed in a plugin box, but more often requires an expandable structural form, that is, a on-site control unit also includes several digital input/output expansion units, which are connected to each other through a bus.
Essentially, the structural form and configuration requirements of the on-site control unit are consistent with the hardware configuration of the modular PLC.