Reference Manual
PMAC 2 Software Reference
PMAC I-Variable Specification 57
Channel Address Channel Address
PFM1 $C004 PFM9 $C044
PFM2 $C00C PFM10 $C04C
PFM3 $C014 PFM11 $C054
PFM4 $C01C PFM12 $C05C
PFM5 $C024 PFM13 $C064
PFM6 $C02C PFM14 $C06C
PFM7 $C034 PFM15 $C074
PFM8 $C03C PFM16 $C07C
Channels 9 – 16 are on an ACC-24P/V2 board
When commanding pulse-and-direction from a PMAC Ultralite through a MACRO ring,
use the address of Register 2 for the MACRO node, as shown in the following table:
Channel Address Channel Address
Node 0 Reg. 0 $C0A2 Node 8 Reg. 0 $C0B2
Node 1 Reg. 0 $C0A6 Node 9 Reg. 0 $C0B6
Node 4 Reg. 0 $C0AA Node 12 Reg. 0 $C0BA
Node 5 Reg. 0 $C0AE Node 13 Reg. 0 $C0BE
Commutation, No Current Loop: If PMAC is commutating Motor x (Ix01 = 1), but not
closing its current loop (Ix82 = 0), two command output values are calculated, which are
written to the Y-register at the address specified in Ix02, plus the Y-register at the next
higher address. Typically, these are two DAC output registers.
To use a pair of DACs on a PMAC(1), the address of the even-numbered DAC of the pair
is used:
Channel Address Channel Address
DAC1 & 2 $C002 DAC9 & 10 $C022
DAC3 & 4 $C00A DAC11 & 12 $C02A
DAC5 & 6 $C012 DAC13 & 14 $C032
DAC7 & 8 $C01A DAC15 & 16 $C03A
Channels 9 – 16 are on an ACC-24P/V board.
To use a pair of DACs on a PMAC2, the address of the A-channel DAC is used to specify
the use of both the A and B-channel DACs. The addresses used are the same as those for
the case when the PMAC2 is not commutating the motor, whether directly or over
MACRO.
In this mode, if bit 16 of Ix02 is set to 1 (e.g. I102=$1C002), then the PMAC will execute
an open-loop commutation known as “direct microstepping” instead of the standard
closed-loop commutation.
Commutation and Current Loop: If PMAC2 is commutating Motor x (Ix01 = 1) and
closing its current loop (Ixx82 > 0), three command output values are calculated, which are
written to the Y-register at the address specified in Ix02, plus the Y-registers at the next
two higher addresses. This mode of operation is not supported on a PMAC(1).
In this mode, Ix02 typically specifies the A-channel output for the channel, which has been
set up for PWM outputs (I9n6 = 0 for Channel n). The following table shows these
addresses: