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Accessory 24E2
I7m01: Servo IC m Phase Clock Frequency Control
Even though the IC is receiving an external phase clock (see I7m07, above), usually it is best to create the
same internal phase clock frequency in the Servo IC. This yields the following constraint:
7 I
m
Solving for I7m01, we get
If I7m00 is the same as I7200 or I6800, I7m01 will be the same as I7201 or I6801.
I7m02: Servo IC m Servo Clock Frequency Control
Even though the IC is receiving an external servo clock (see I7m07, above), usually it is best to create the
same internal servo clock frequency in the Servo IC. This means that I7m02 for the IC should be set the
same as I7202 on a UMAC Turbo, or the same as I6802 on a Turbo PMAC2 Ultralite.
I7m03: Servo IC m Hardware Clock Frequency Control
The hardware clock frequencies for the Servo IC should be set according to the devices attached to it.
There is no reason that these frequencies have to be the same between ICs. There is seldom a reason to
change this value from the default.
Single-Channel I-Variables
The single-channel setup I-variables for Channel n of Servo IC m work the same on an ACC-24E2 as they
do on a Turbo PMAC2 itself. Each Servo IC has four channels n, numbered 1 to 4. For the first
(standard) Servo IC on the ACC-24E2, the channel numbers 1 – 4 on the Servo IC are the same as the
channel numbers 1 – 4 on the board. The most important variables are:
I7mn0: Servo IC m Channel n Encoder Decode Control
Typically, I7mn0 is set to 3 or 7 for x4 quadrature decode, depending on which way is up. If the channel
is used for open-loop stepper drive, I7mn0 is set to 8 to accept internal pulse-and-direction, or to 0 to
accept external pulse-and-direction (e.g. from an ACC-8S). It is set to 12 if the channel is used for
MLDT feedback.
I7mn2: Servo IC m Channel n Capture Control
I7mn2 determines whether the encoder index channel, an input flag, or both, are used for the capture of
the encoder position.
I7mn3: Servo IC m Channel n Capture Flag Select
I7mn3 determines which input flag is used for encoder capture, if one is used.
I7mn6: Servo IC m Channel n Output Mode Select
I7mn6 determines whether the A and B outputs are DAC or PWM, and whether the C output is PFM
(pulse-and-direction) or PWM. Typically, it is set to 0, for 3-phase PWM, or to 3 for DACs and PFM.
Connections
2
*
PWMFreq
PhaseFreq
+
=
7 I
m
00
*
(
7 I
m
01
) 1
+
=
00
*
(
7 I
m
01
) 1
I
6800
I
7200
*
I (
=
7 I
m
01
7 I
m
I
6800
*
I (
6801
=
7 I
m
01
7 I
m
00
(
kHz
)
=
{
Integer
}
+
{UMAC Turbo}
I
7200
*
I (
7201
) 1
+
{Turbo PMAC2 Ultralite}
*
I (
6801
) 1
+
7201
) 1
−
{UMAC Turbo}
1
00
+
) 1
−
{Turbo PMAC2 Ultralite}
1
17
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