Ndrive HP 10/20/30 User’s Manual
Technical Details
www.aerotech.com 3-7
3.2. Position Synchronized Output (PSO) / Laser Firing
The Ndrive includes a Position Synchronized Output (PSO or Laser Firing) option. This
feature may be programmed to generate an output synchronized to axes positions, based
upon a user-defined trigger condition, most typically, but not limited to firing a laser. The
Ndrive offers three levels of laser firing, single axis (std.) and two and three axis. Trigger
signals may be derived from the primary encoder channel, secondary encoder channel,
either of the two optional SSI Net ports or a software trigger. Both SSI Net ports may
provide axes encoder signals or marker signals to/from another Ndrive at a maximum of
a 20 MHz. data rate (50 nsec. minimum edge separation). Single axis tracking is limited
to a 20 MHz. data rate and multi-axis to a 5 MHz tracking rate. The PSOTRACK
command may be used to scale the encoder input signal to limit the maximum tracking
rate. The synchronized output pulse is solely generated within sophisticated and versatile
high-speed hardware, allowing minimal delays between the trigger condition and the
output. Single axis PSO laser firing latency is 200 nanoseconds. -DUALPSO and -
TRIPLEPSO laser firing latency is 275 nanoseconds, not including the propagation delay
of the output device. Refer to Figure 3-4 for a basic single-axis block diagram of the PSO
capabilities, or Figure 3-5 and Figure 3-6 for a more detailed block diagram of the multi-
axis capabilities that also apply to single-axis firing. The output may be either an open-
collector output (dedicated PSO output or user output 11) or a differential RS-422 output.
The opto-isolated output is available in three different configurations as shown in
Table 3-9. Additionally, the PSO options provide Data Capture and Data Update
capabilities, also shown in Figure 3-5 and Figure 3-6.
For programming information,
refer to the Nview HMI Help.
Table 3-9.
PSO Encoder Signal Sources and Pre-Scaling Methods
Encoder Signal
Source
Max. Data Rate
(w/o pre-scalar)
Encoder Input
(pre-scalar)
Encoder Output
(pre-scalar)
Primary Encoder
32 Mhz.
PSOTRACK cmd.
CfgFbkEncQuadDivider
axis parameter (MXH only)
Secondary Encoder
32 Mhz.
PSOTRACK cmd.
None
SSI Net Ports 1 and 2 20 Mhz.
PSOTRACK cmd.
CfgFbkEncMxhSetup axis
parameter
Figure 3-4.
PSO Diagram – Basic Single Axis Firing
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