User`s manual

Product Overview

GFK-1742A Chapter 1 Product Overview 1-5

Motion Program/CTL Faceplate Inputs

•

Delays associated with motion program control or branching via faceplate CTL inputs are

equal to a position loop update time interval (0.5 to 2 ms)

plus

the input filter delay (5 ms

typical for 24 volt CTL inputs or 10

s for 5 volt CTL inputs). See tables 1-1, 1-2, and 1-3

for position loop update times.

Local Logic

•

Delays associated with Local Logic data updates are based upon the position loop update time

interval (see next section, “DSM314 Servo Loop Update Times”) and are not related to the

PLC scan. Therefore, Local Logic programs can utilize rapidly changing DSM internal data

that cannot be utilized by the PLC CPU due to the PLC to DSM data transfer time and the

PLC’s longer scan time.

DSM314 Servo Loop Update Times

When controlling a GE Fanuc digital AC servo, the DSM314 uses the loop update times shown in

Table 1-1.

Table 1-1. GE Fanuc Digital Servo Loop Update Times

Motor Current / Torque Loop: 250 microseconds

Motor Velocity Loop: 1 millisecond

Motor Position Loop: 2 milliseconds

When controlling an Analog servo, the DSM314

without

Local Logic uses the loop update times

shown in Table 1-2.

Table 1-2. Analog Servo Loop Update Times without Local Logic

1-Axis Position Loop without Local Logic: 0.5 milliseconds

2-Axes Position Loop without Local Logic: 1 millisecond

3-4 Axes Position Loop without Local Logic: 2 milliseconds

When controlling an Analog servo, the DSM314

with

Local Logic uses the following loop update

times shown in Table 1-3. The loop update rates with Local Logic are longer since Axis #4 time

slot is used to calculate the Local Logic function.

Table 1-3. Analog Servo Loop Update Times with Local Logic

1 Axis Position Loop with Local Logic: 1 millisecond

2 –3 Axes Position Loop with Local Logic: 2 milliseconds