Introduction

In the MMI system, two SR4 controllers are used. Each can control up to four SMC systems. During operation, a three byte net command (address), consisting of three bytes, is prefixed to a motion control command string. When the selected SR4 detects its address, a serial path is connected to the addressed SMC by a 1 to 4 serial data multiplexer. The motion command is then passed to the SMC. The command terminator character (carriage return) resets the multiplexer. Each motor command string must start with a net controller address. The controller address compares to the setting of the SR4 address switches in the MMI. The multiplex code selects any combination of the four output paths to the SMCs. For example, one motor system, at a time, is selected for setup commands and then up to four motors can be directed to execute (Go) simultaneously. When requesting information from a SMC motor system, only one of the eight can be selected.

When a motor system is performing an operation, its Busy signal is input to the SR4's status register. To monitor the busy status of the SMCs, a Read command (address), again consisting of three bytes, is sent to the net controller. The SR4 will return an ASCII character equal to a binary number. This number indicates the status of all four SMCs. Refer to the net ID address table in this manual.

The host to MMI serial port is wired with standard RS-232 (IBM type) DB-9 connectors. Each MMI has two connectors. The first goes to the host computer and the second to the next MMI controller in the daisy-chain. The last controller's second connector must terminated with the "loop jumper" DB9 plug.

The MMI normally operates in standard RS-232 format using ASCII character mode at 1200 baud which supports the EEPROM memorys on the motor cards. Optional baud rates up to 57K baud are possible. Parity is none, 8 data bits, and 1 stop bit.