Motion MMI-8S - Manual (Page 19)

Hardware Configuration
The SMC controller card contains the CY 545 motion controller, EEprom memory, memory
latches (2 each), RS-232 receiver / driver, LED status lites and standard crystal (11 MHZ). Refer to
the Rate Table in the CY545 manual.
Serial Format
The SMC is connected as a RS-232 serial device and communicates with the host computer
through the SR4 network. The serial format is configured in the following manner: ASCII
characters, 1200 Baud, 8 data bits, no parity, and one stop bit. The CTS (Clear To Send) feature
of the 545 (User Bit 6) is used as the hardware hand-shake to control communication between the
host and the 545. When the 545 is busy, it will set the CTS signal to the SR4 status register as a
request to hold off transmission.
During operation from memory or when homing, the CTS function is not 100% busy; pulses
on/off each instruction. This is to allow interruption of routines by the host computer sending a
stop command (0 or CR). If other data is sent, incorrect operation will result. To set the SMC
100% busy during operations: (1) disable the CTS function with the Mode command. User Bit 6
will set HI or busy. (2) As the last instruction, in the memory routine, re-enable the CTS.
NOTE: the correct Mode command to defeat the CTS is: o 080h.
the correct Mode command to enable the CTS is: o 0a0h
(Any hex value starting with a letter must be preceded by a zero)
Memory Format. The memory is configured as 2K bytes of EEPROM (RAM is optional). It is not
possible to access memory above address 2047. Note that the memory is in pages of 256 bytes;
the CY545 does not allow Jump, Test, or Loop operations across page boundries. The pointer
command (Y) is used to move across boundries. A feature of the 545 memory system, the Auto-
Start function which recognizes special character flags in the first bytes of memory as a
command to run the following program at power-on, is not used in the MMI.
Home Function. This system uses an optical sensor to establish the starting reference or
"Home" position at power-on; refer to the Home command (H). Lash-Compensation is included in
the home routine. A major advantage of this system is Slip-Detection which provides operation
to + zero steps. See Installation and Test for a detailed home procedure.
Limit Loop Function. The CW-CCW Limits function of the 545, pin 4 & 5, is not used in this
system. Instead, the driver card will go "free or ABoRt" (CURRENT-OFF) when the Limit Loop is
opened (Fail-Safe, Hard-Soft limits). This Limit Loop is enabled by User Bit 0. Refer to the
Appendix B section of this manual.