User guide

142 6000 Series Programmer's Guide
ANI Analog Input Interface (only servo controllers with ANI option)
Refer to your product's
Installation Guide for
ANI connection
information.
6000 Series servo controllers with the -ANI option offer ±10V, 14-bit analog inputs (referred
to as “ANI” inputs). Each input has an anti-aliasing filter and is sampled at the servo sample
rate (set with the SSFR command). The voltage value of the ANI inputs can be transferred to
the terminal with the TANI command, or used in an assignment or comparison operation with
the [ANI] command (e.g., IF(1ANI<2.4)). The position value of the ANI inputs can be
transferred to the terminal with the TPANI command, or used in an assignment or comparison
operation with the [PANI] command (e.g., WAIT(1PANI>421)).
Three common applications of the ANI inputs are:
• Position command to the control loop (e.g., as a master axis in Following mode)
• Position feedback to the control loop
• A force or torque feedback signal
Programming
Example
The portion of 6000 code below (for two axes of control) demonstrates how to read the analog
inputs into the controller and set the commanded analog output of each axis to that value. If
you have a torque drive, this provides open-loop torque control.
SGP0,0 ; Turn off servo proportional feedback gain
SGI0,0 ; Turn off servo integral feedback gain
SGV0,0 ; Turn off servo velocity feedback gain
SGAF0,0 ; Turn off servo acceleration feedforward gain
SGVF0,0 ; Turn off servo velocity feedforward gain
SOFFS0,0 ; Set offset to zero (analog output will be 0 volts)
L ; Enter an infinite loop
VAR1=1ANI ; Read value of ANI analog input #1 into variable #1
VAR2=2ANI ; Read value of ANI analog input #2 into variable #2
SOFFS(VAR1),(VAR2) ; Assign voltages from ANI analog inputs #1 & #2 to the
; analog output for axes #1 & # 2, respectively
T.01 ; Set time delay to 10 milliseconds
LN ; End loop
4-20 mA
Feedback
The analog inputs can be used to monitor a process using 4-20 mA feedback. This is
accomplished by simply attaching a resistor from the ANI input to AGND (e.g., a 500Ω, 1%
resistor would facilitate a 2-10V input). In this way, the current is converted to a voltage that
can be monitored with the ANI input. The PSET command can be used to set the input
readings to user coordinates.
ANI as a
Feedback
Device
The ANI analog inputs, when selected as a feedback source with the SFB command, is assumed
to provide position information. With this feedback it is possible to solve applications that
require positioning to a voltage, rather than positioning to a known position. Some example
applications are as follows:
• Using a potentiometer as feedback (mechanical motion is mimicked by the 6000
controller)
• Maintaining a force while position changes due to fluid evacuating a chamber
• Opening or closing a valve as another process changes
Auxiliary Analog Output (“half axis” — AT6n50 only)
☞
See Installation
Guide for connection
instructions.
The AT6n50 offers an auxiliary analog output (ANA), located at terminal #3 on the AUX
connector. This output provides ±10V with an accuracy of ±5%, and is derived from an 8-bit
digital-to-analog converter.
To control the voltage at this output, use the OUTANA command. Syntax is OUTANA<r>,
where <r> is the desired output in volts with a range of -10 to +10 (e.g., OUTANA5.ØØ sets
the analog output to +5.00 volts). The default output is zero volts. The ANA output is not
affected by the state of the enable (ENBL) input.