主轴伺服提供加工各类工件所需的切削功率，因此，只需完成主轴调速及正反转功能。但当要求机床有螺纹加工、准停和恒线速加工等功能时，对主轴也提出了相应的位置控制要求，因此，要求其输出功率大，具有恒转矩段及恒功率段，有准停控制，主轴与进给联动。与进给伺服一样，主轴伺服经历了从普通三相异步电动机传动到直流主轴传动。随着微处理器技术和大功率晶体管技术的进展，又进入了交流主轴伺服系统的时代。

Omron NT620C-ST141B-E (NT620CST141E) is an NT series touch screen with operating interface. The size of the display touch screen is 180.5mm x 263.5 (7.11 inches x 10.37 inches). The front panel measures 196mm x 275 (7.72 inches x 10.83 inches), has a depth of 76.8mm (3.02 inches) and weighs 9.7 pounds. The LCD screen resolution of NT620C-ST141B-E is 640 x 480 pixels. This touch screen is black and uses 8 colors. The DC voltage of NT620C-ST141B-E operator interface is 24V, which generates 20W.

NT620C-ST141B-E can use NT series support tools to quickly make graphics and programs. Easy-to-use software is also integrated in the touch screen, allowing users to perform the aforementioned operations. The NT620C-ST141B-E can also be quickly fixed through its communication with the host link or NT link communication, as described below.

There are many communication methods for the NT620C-ST141B-E touch screen: host link, NT 1:1 and 1:N link and memory link. The host link is built into the interface. This host link allows communication between the interface and the CPU module in CQM1 configuration. The baud rate of this communication ranges from 9600 to 19,200 bps, and the response speed is usually 0.5 seconds. NT link 1.1 of NT620C-ST141B-E is the fastest communication mode of Omron. It reacts within 0.2 seconds at most. NT link 1:N allows multiple connections between multiple machines. The memory link allows direct connection from Omron third-party host through RS-232C or RS-422A communication.