Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 207
Note:
By default, the index channels of a DSPGATE2 MACRO IC are not used on a
Turbo PMAC2. The index inputs are the “alternate” uses of pins on the
multiplexer port.
I68n5/I69n5 MACRO IC Channel n* Encoder Index Gate State/Demux Control
Range: 0 - 3
Units: none
Default: 0
Note:
This I-variable is active only if the MACRO IC is present, and is a DSPGATE2 IC.
The presence and type of MACRO ICs are reported in I4902 and I4903.
I68n5 and I69n5 are 2-bit variables that control two functions for the index channel of the encoder.
When using the gated index feature of Channel n* of a DSPGATE2 MACRO IC for more accurate
position capture (I68n4/I69n4 = 1), bit 0 of I68n5 and I69n5 controls whether the raw index-channel
signal for Encoder n* (n* = 1 to 2) on the MACRO IC is passed through to the position capture signal
only on the high-high quadrature state (bit 0 = 0), or only on the low-low quadrature state (bit 0 = 1). For
MACRO ICs 0 and 2, n = n*; for MACRO ICs 1 and 3, n = n* + 5 (i.e. I6815 controls MACRO IC 0
Channel 1; I6975 controls MACRO IC 3 Channel 2).
Bit 1 of I68n5 and I69n5 controls whether the Servo IC de-multiplexes the index pulse and the three hall-
style commutation states from the third channel based on the quadrature state, as with Yaskawa
incremental encoders. If bit 1 is set to 0, this de-multiplexing function is not performed, and the signal on
the C channel of the encoder is used as the index only. If bit 1 is set to 1, the Servo IC breaks out the
third-channel signal into four separate values, one for each of the four possible AB-quadrature states. The
de-multiplexed hall commutation states can be used to provide power-on phase position using Ixx81 and
Ixx91.
Note:
Immediately after power-up, the Yaskawa encoder cycles its AB outputs forward
and back automatically through a full quadrature cycle to ensure that all of the hall
commutation states are available to the controller before any movement is started.
However, if the encoder is powered up at the same time as the Turbo PMAC, this
will happen before the Servo IC is ready to accept these signals. Bit 2 of the
channel’s status word, Invalid De-multiplex will be set to 1 if the Servo IC has not
seen all of these states when it was ready for them. To use this feature, it is
recommended that the power to the encoder be provided through a software-
controlled relay to ensure that valid readings of all states have been read before
using these signals for power-on phasing.
I68n5 and I69n5 have the following possible settings:
 I68n5/I69n5 = 0: Gate index with high-high quadrature state (GI = A and B and C), no demux
 I68n5/I69n5 = 1: Gate index with low-low quadrature state (GI = A/ and B/ and C), no demux
 I68n5/I69n5 = 2 or 3: De-multiplex hall and index from third channel, gating irrelevant
Note:
By default, the index channels of a DSPGATE2 MACRO IC are not used on a
Turbo PMAC2. The index inputs are the alternate uses of pins on the multiplexer
port.