Specifications

4.3 COMMUNICATIONS PROTOCOL

The remote PC communication program should be set for 19.2 K baud rate with 8 data bits, 1

stop bit, and no parity (8N1). The Pyxis is preset for these values and will not respond to other

settings and cannot be changed. Tables 4-1 through 4-7 below describe in detail the commands

used to control and communicate with the Pyxis. To establish communications with the Pyxis,

plug in the power supply and wait for the Pyxis to complete the homing routine. Once the homing

routine is complete, the unit will enter the serial loop function and await commands from the PC.

To verify that the Pyxis is in the serial loop, send the CCLINK command which the Pyxis will

reply with a “!” LF CR. In the tables below, the commands comprise upper case letters as shown.

The small case n represents any number from 0 to 9. The small case x represents any character

since they are ignored. LF represents the line feed control character 0A hex. CR represents the

carriage return control character 0C hex. It is necessary to send the command as one data stream

with normal pacing between characters. Typing in the characters one at a time with a terminal

program will not work.

Command

Return

CCLINK

! CR LF

Function:

This command checks to see if the Pyxis is in the serial loop mode. A successful return

from this command (!) is required before the Pyxis will accept any other user commands.

Trouble Shooting:

If “!” is not returned check to see if the Pyxis has completed its homing routine. Check

baud rate and serial connection.

Table 4-1. Serial mode command check.

Command

Return

CHOMES

! (for every step made) F (when homing is compete)

Function:

This commands the Pyxis to rotate and find the home position magnet and then return to

position angle 0.

Trouble Shooting: An ER=1 is returned if the magnet cannot be found. This might happen

if the unit is jammed and cannot rotate properly.

Table 4-2. CHOMES Command finds PA (position angle) 0.