Delta Tau GEO BRICK LV User Manual

 

 

When accessing a Q-variable from a motion program statement (including kinematic subroutines), the Q-
variable belonging to the coordinate system running the program is being used.  If a different coordinate 
system runs the same motion program, it will use different Q-variables. 

When accessing a Q-variable from a PLC program statement, the Q-variable for the coordinate system 
that has been addressed by that PLC program with the ADDRESS command is being used.  Each PLC 
program can address a particular coordinate system independent of other PLC programs and independent 
of the host addressing.  If no ADDRESS command is used in the PLC program, the program uses the Q-
variables for C.S. 1. 

Type of Memory Used 

Q-variables can be located in either the main memory or in the supplemental battery-backed parameter 
memory (if Option 16 is ordered).  If I46 is set to 0 (default) or 1, the Q-variables are located in the main 
memory, which has fast access (1 wait state) but whose values are not retained without a SAVE command 
copying the values to flash memory.  On power-up/reset, the last saved values are copied from flash 
memory into the active variable registers in RAM. 

If I46 is set to 2 or 3, the Q-variables are located in the Option 16 battery-backed RAM, which has slow 
access (9 wait states) but whose values are retained by the battery automatically when power is removed. 

Special-Use Q-Variables 

Several Q-variables have special uses to watch for.  The ATAN2 (two-argument arctangent) function 
automatically uses Q0 as its second argument (the cosine argument).  The READ command places the 
values it reads following letters A through Z in Q101 to Q126, respectively, and a mask word denoting 
which variables have been read in Q100.  The S (spindle) statement in a motion program places the value 
following it into Q127. 

If the application uses kinematic subroutines to convert between tool-tip (axis) positions and joint (motor) 
positions, variables Q1 – Q10 and possibly Q11 – Q19 for the coordinate system are used for the axis data 
in these subroutines (Q1 – Q9 are for axis positions; Q10 tells whether PVT moves are being converted; if 
PVT moves are converted, Q11 – Q19 are for axis velocities).  If using the kinematic subroutines, make 
sure not to use the Q-variables employed in the subroutines for any other purpose. 

M-variables are provided to permit easy user access to Turbo PMAC’s memory and I/O space.  Generally, 
a definition only needs to be made once, with an on-line command.  The SAVE command must be used to 
retain the definition through a power-down or reset.  Define an M-variable by assigning it to a location 
and defining the size and format of the value in this location.  An M-variable can be a bit, a nibble (4 
bits), a byte (8 bits), 1-1/2 bytes (12 bits), a double-byte (16 bits), 2-1/2 bytes (20 bits), a 24-bit word, a 
48-bit fixed-point double word, a 48-bit floating-point double word, or special formats for dual-ported 
RAM and for the JTHW multiplexer port.   

There are 8192 M-variables (M0 to M8191), and as with other variable types, the number of the M-
variable may be specified with either a constant or an expression: M576 or M(P1+20). 

M-Variable Definitions 

The definition of an M-variable is done using the defines-arrow (->) composed of the minus sign and 
greater than symbol.  Generally, a definition needs to be made only once, with in an on-line command, 
because it is stored in battery-backed RAM or saved to flash memory.  The M-variable thus defined may 
be used repeatedly. 

An M-variable may take one of the following types, as specified by the address prefix in the definition: 

X: 

1 to 24 bits fixed-point in X-memory 

Y: 

1 to 24 bits fixed-point in Y-memory 

D: 

48 bits fixed-point across both X- and Y-memory