Motion MMI-8S - Manual (Page 10)

ECHO MODE
In the MMI network system, with two network cards, it is necessary to engage the CY233 pass-
through (echo-all) mode. This allows commands originating in a motion channel (SMC) to be
passed through successive SR4 cards down-stream in the network loop. A typical example is the
SMC system query commands. The J command format consists of a mode character (J), the ID
number (two hex characters; the second is always F), and the terminator (carriage return).
A typical command would be J0F<; the 0 is the address of the first SR4 card and the F indicates a
SR4 only message; J1F is the second card address. Each SR4 in the daisy-chain network must
be sent a J command during start-up procedure.
ID AND STATUS CODES
Refering to the following table, note that the codes seem confusing in that they are not an orderly
sequence of decimal numbers. They, in fact, are based on their hex-decimal values from 0 to F
(hex) . Also as the active selection signal is a LOW or 0 volts, the sequence is inverted. For
example, all devices selected is a 0 (zero) code or address; all bits are low. No devices selected
is F; all bits HI (+5 volts). Therefore, selection of the first device or E indicates 1 bit is LOW; all
others are HI. Note that the codes for the individual motor controllers are therefore E (motor #1),
D (motor #2), B (motor #3), and 7 (motor #4). The other codes allow selection of any combination
of motors. The BUSY codes correspond to these selections with the @ indicating all BUSY
followed by A to O (none busy) in decending order. Refer to PROGRAMMING section for
examples of code selection.