Introduction
This document describes a project done for the Neuromuscular Control Lab at the Department of Biomedical Engineering , McGill University. The work involved modifying a real-time digital control system used to control a high-performance hydraulic actuator used in human motor control studies. The control system is implemented on a pair of Transputers (MIMD-parallel microprocessors), resident in a 486-PC host. The host PC is connected to a master workstation via Ethernet.
The primary goal of this project was to provide the system with a convenient user interface for transferring data and control parameters between the two networks. To accomplish this, a new protocol was devised which allows a client program running on the workstation to leave messages, which the Transputer program (also a client program) can pick up and act on; communication from the Transputer to the workstation client is done in the same manner.
As the project neared the half-way point, it was discovered that parts of the current system were incompatible with newly-acquired workstations (DEC AXP's running OSF1); hence, the main goal of the project was suspended while porting issues were considered.
This document starts with a general introduction to Transputers, followed by a specific discussion of the system under considerations. Interfacing transputer networks to host stations is described next; this is where the source of incompatibility lay. Solutions to the porting problem are presented, and hints for future work are given. Next, the new ("post office") server protocol is described. The document concludes with a short discussion of the hardware available for digital control, and the expected lifespan of the current Transputer system.