User's Manual

PMAC2 User Manual
16 Setting Up PMAC2 for Direct PWM Control
Hardware Setup
The connection between PMAC2 and the direct PWM digital amplifier is almost always made through an
interface board. Typically, this interface board works for 2 axes, connecting with a short 100-strand flat
cable to one of PMAC2’s machine connectors. The interface board has connectors to the amplifiers, to
the position feedback sensors, and to any flags used (overtravel limits, home, etc.).
Existing Delta Tau boards for this style of connection at the time of this writing are:
• Acc-8F PWM Interface (requires A/D converters in the amplifier)
• Acc-8K1 Fanuc C- & S-Series Drive Interface
• Acc-8K2 Kollmorgen IPB Drive Interface
All of the digital amplifier interface lines on PMAC2 itself are digital 5V signals. There is no optical
isolation on PMAC2; any optical isolation must be provided on an interface board or in the amplifier.
Note:
Usually the hardware connection between PMAC2 and the digital amplifier is
made with integrated cables, either directly to the amplifier, or to an interface
board. The following section details the individual signal line connections for
those users who do not have an integrated connection solution. If using a pre-
designed connection system, refer to the appropriate manual for connection
information.
PWM Signal Outputs
When PMAC2’s digital current loop is used, the format of the output commands is virtually always digital
pulse-width-modulated (PWM) signals. For each machine interface channel, PMAC2 has three pairs of top
and bottom PWM signals, which can be used for the half-bridges of a 3-phase motor. Each of these six
output signals is a differential line-driver pair, for a total of 12 PWM pins. These pins are named:
• PWMATOPn+PWMATOPn-(Phase A top transistor command)
• PWMABOTn+PWMABOTn-(Phase A bottom transistor command)
• PWMBTOPn+PWMBTOPn-(Phase B top transistor command)
• PWMBBOTn+PWMBBOTn-(Phase B bottom transistor command)
• PWMCTOPn+PWMCTOPn-(Phase C top transistor command)PWMCBOTn+PWMCBOTn-(Phase
C bottom transistor command)
where n is the PMAC2 channel number. These pins have alternate uses as DAC signals and pulse-and-
direction outputs; PMAC2 parameters are used to configure them as PWM outputs (see below).
ADC Interface Signals
The actual phase current information is almost always brought in from serial analog-to-digital converters
(ADCs). For a multi-phase motor, this information is brought back for two of the phases, what PMAC
calls the A and B phase. These ADCs are not on the PMAC2; they are either in the amplifier, or on the
interface board. Four digital interface signals are required for each pair of ADCs; the two serial inputs, an
output clock, and an output strobe. Each of these signals is differential, for a total of eight pins. These
pins are named:
Note:
The on-board multiplexed Option 12 ADCs are not suitable for current-loop
feedback.
• ADC_DAAn+ADC_DAAn-(Phase A ADC serial input data)
• ADC_DABn+ADC_DABn-(Phase B ADC serial input data)
• ADC_CLKn+ADC_CLKn-(ADC clock output)
• ADC_STBn+ADC_STBn-(ADC strobe output)