PMAC Quick Reference Guide A coordinate system is addressed by a &n command, where n is the number of the coordinate system, with a range of 1 to 8, inclusive. This coordinate system stays the one addressed until another &n command is received by the card. For instance, the command line &1B6R&2B8R tells Coordinate System 1 to run Motion Program 6 and Coordinate System 2 to run Motion Program 8. There are a variety of types of coordinate-system-specific commands. Axis definition statements act on the addressed coordinate system, because motors are matched to an axis in a particular coordinate system.
Since it is a coordinate system that runs a motion control program, all program control commands act on the addressed coordinate system. Q-Variable assignment and query commands are also coordinate system commands, because the Q-Variables themselves belong to a coordinate system. Some on-line commands do not depend on which motor or coordinate system is addressed. For instance, the command P1=1 sets the value of P1 to 1 regardless of what is addressed. Among these global on-line commands are the buffer management commands. PMAC has multiple buffers, one of which can be open at a time. When a buffer is open, commands can be entered into the buffer for later execution.
Control character commands (those with ASCII values 0 - 31D) are always global commands. Those that do not require a data response act on all cards on a serial daisychain. These characters include carriage return , backspace , and several special-purpose characters. This allows, for instance, commands to be given to several locations on the card in a single line, and have them take effect simultaneously at the at the end of the line ( &1R&2R causes both Coordinate Systems 1 and 2 to run). Buffered (Program) Commands As their name implies, buffered commands are not acted on immediately, but held for later execution.
PMAC has many program buffers – 256 regular motion program buffers, eight rotary motion program buffers (1 for each coordinate system), and 32 PLC program buffers. Before commands can be entered into a buffer, that buffer must be opened (e.g. OPEN PROG 3 , OPEN PLC 7 ). Each program command is added onto the end of the list of commands in the open buffer; to replace the existing buffer, use the CLEAR command immediately after opening to erase the existing contents before entering the new ones. After finishing entering the program statements, use the CLOSE command to close the opened buffer.
Computational Features I-Variables I-Variables (initialization, or setup variables) determines the personality of the card for a given application. They are at fixed locations in memory and have pre-defined meanings. Most are integer values, and their range varies depending on the particular variable. There are 1024 I-Variables, from I0 to I1023, and they are organized as follows: I0 -- I79: General card setup I80 -- I99: Geared Resolver setup I100 -- I184: Motor #1 setup I185 -- I199: Coordinate System 1 setup I200 -- I284: Motor #2 setup I285 -- I299: Coordinate System 2 setup I800 -- I884: Motor #8 setup I885 -- I899: Coordinate System 8 setup I900 -- I979:
Encoder 1 - 16 setup I980 -- I1023: Reserved for future use Values assigned to an I-Variable may be either a constant or an expression. The commands to do this are on-line (immediate) if no buffer is open when sent, or buffered program commands if a buffer is open. Examples: I120 = 45 I120 = (I120+P25*3) 32 Programming PMAC