Accessory 24E2S
UMAC Software Setup
15
Multi-Channel I-Variables
There are several multi-channel I-variables that must be set up properly for proper operation of the Acc-
24E2 in a Turbo PMAC system. The most important are:
I7m07: Servo IC m Phase/Servo Clock Direction
This variable should be set to 3 for any Servo IC on an Acc-24E2 so it inputs its phase and servo clocks
from signals generated on the Turbo PMAC itself.
I7m00: Servo IC m MaxPhase/PWM Frequency Control
Typically, this will be set to the same value as the variable that controls the system clocks: I7000 on a
non-Ultralite Turbo PMAC2, or I6800 on a Turbo PMAC2 Ultralite. If a different PWM frequency is
desired, or the Acc-24E2 is used with a Turbo PMAC in which the system clock frequencies are set by
jumpers, then the following constraint should be observed in setting this variable:
}
Integer
{
PhaseFreq
)
kHz
(
PWMFreq
*
2
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:
)
1
7001
I
(
*
7000
I
)
1
01
m
7
I
(
*
00
m
7
I
{Non-Ultralite Turbo PMAC2}
)
1
6801
I
(
*
6800
I
)
1
01
m
7
I
(
*
00
m
7
I
{Turbo PMAC2 Ultralite}
Solving for I7m01, the result is:
1
00
m
7
I
)
1
7001
I
(
*
7000
I
01
m
7
I
{Non-Ultralite PMAC2}
1
00
m
7
I
)
1
6801
I
(
*
6800
I
01
m
7
I
{Turbo PMAC2 Ultralite}
If I7m00 is the same as I7000 or I6800, I7m01 will be the same as I7001 or I6801. If the Acc-24E2 is
interfaced to a Turbo PMAC board, it should be set by calculation to obtain the same phase clock
frequency as that set by the jumpers on the Turbo PMAC.
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 I7002 on a non-Ultralite Turbo PMAC2, or the same as I6802 on a Turbo PMAC2 Ultralite.
When connected to a Turbo PMAC, I7m02 should create the same division from the phase clock as
jumpers E3 – E6 do on the Turbo PMAC.
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. For the second (optional) Servo IC on the Acc-24E2, the channel numbers 1 – 4 on the
Servo IC correspond to board channel numbers 5 – 8. The most important variables are:
