Reference Manual

PMAC 2 Software Reference
PMAC I-Variable Specification 69
port address is also read and treated as a geared-down resolver, with I9x specifying the gear
ratio. If I8x is also set greater than 0, the following R/D converter at the same multiplexer port
address is read and treated as a third resolver geared down from the second, with I8x
specifying that gear ratio.
MACRO Station Parallel Data Read: If Ix10 is set to $74000n or $F4000n, Motor x will
expect its power-on position from a parallel data source through a MACRO Station or
compatible device. In this mode, ‘n’ specifies the MACRO node number at which PMAC will
read the position value itself. Set-up variable MI11x for the matching node on the MACRO
Station tells the Station how to read the parallel data source connected to it.
Bit 23 of Ix10 specifies whether the position is interpreted as an unsigned value (Bit 23 = 0,
making the first hex digit a 7) or as a signed value (Bit 23 = 1, making the first hex digit an F).
Set Ix10 to $74000n for unsigned, or to $F4000n for signed.
EnDat Data Read (Geo PMAC only): If Ix10 is set to $75wxyz or $F5wxyz on a Geo
PMAC, Motor x will expect its power-on servo position from the optional EnDat interface that
can be built in to the Geo PMAC.
Bit 23 of Ix10 specifies whether the position is interpreted as an unsigned value (Bit 23 = 0,
making the first hex digit a 7) or as a signed value (Bit 23 = 1, making the first hex digit an F).
Set Ix10 to $75wxyz for unsigned, or to $F5wxyz for signed.
The third and fourth hex digits (wx) specify the number of bits of EnDat absolute position to
be read, as a hex value. For example, if 20 bits were to be read, these two hex digits would be
set to 14.
The fifth hex digit (y) specifies the shift of the data read, permitting the user to match the
resolution properly with that of the ongoing position. The data is first shifted left 10 bits, then
shifted right by “y” bits, so “y” should be set to (NetRightShift + 10). The object is to end up
with data whose LSB is equal to one quadrature count (1/4-line) of the encoder. Most
commonly, the data comes in with the LSB equal to 1/4 of a quadrature count (1/16-line),
requiring a net right shift of 2 bits, so “y” should be a hex digit of “C” (12 decimal).
The sixth hex digit (z) specifies the channel number used, whether the data is negated, and
whether it should be matched to ongoing digital quadrature or analog sinusoidal feedback.
Bits 1 and 0 together express the channel number minus one as a value from 0 to 3 (so Channel
1 to 4). Bit 2 is set to 0 if the ongoing feedback is analog sinusoidal processed through the
high-resolution conversion (format $F) in the conversion table, or to 1 if the ongoing feedback
is digital quadrature. Bit 3 is set to 0 to use the data without negation, or to 1 to negate the
data before using. Negating the data reverses the direction sense; this control is used to match
the direction sense of the ongoing feedback as set by I9n0.
Presently, Channels 1 and 2 are supported, and EnDat is almost always used with interpolated
sinusoidal ongoing feedback, so “z” is set to 0 or 8 for Channel 1 (regular or negated,
respectively), or to 1 or 9 for Channel 2 (regular or negated, respectively).
Motor Safety I-Variables
Ix11 Motor x Fatal (Shutdown) Following Error Limit
Range
0 .. 8,388,607
Units
1/16 Count
Default
32000 (2000 counts)
Remarks
Ix11 sets the magnitude of the following error for Motor x at which operation will shut
down. When the magnitude of the following error exceeds Ix11, Motor x is disabled