Load cells, serial interface

One advantage of serial interfaces is that two-way communication is possible. For example, a tare command can be issued to a load cell. 

A three way interaction among the robot controller, the cell host computer and a microcomputer was used to provide the robot controller with the capability to load/unload part programs automatically. The cell host computer, obviously, dictates the part to be processed. The robot controUer does not have either local storage or capability to selectively load required files. A microcomputer (IBM-AT) is used to interact with the robot via a RS-232 serial port(4800 baud rate). This microcomputer provides the necessary storage for the files related to aU parts in the cell. The robot does not have additional communication ports to be able to link to the cell host. However it has 32 TTL compatible Input/Output lines. We used 16 of th to interact with digital Input/Output interface of an OPTOMUX data acquisition system which in turn is linked via a RS-232 (9600 baud) port to the cell host Though the cell host can provide file storage, increased load on the cell host could not be justified. A dedicated microcomputer could provide a faster download and realtime response. As will be described later, this microcomputer is also used to monitor the robot activities in realtime. 

---