GDtool v2.5

VSD-E Servo Drive Configuration Software

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Introduction

This document describes how to get started with Granite Devices VSD-E servo drive configuration.

Before servo drive can be used in you application, drive requires that minimal set of parameter are

configured for proper operation.

Servo drive parameters are configured using software called GDtool. Configuration parameters are

stored into drive microcontroller’s non-volatile memory and communication between drive and

GDtool is implemented using device specific SPI-protocol via USB-cable.

System requirements:

• GDtool software installed from GDtool CD

• USB device driver installed from GDtool CD

• USB-adapter cable

• VSD-E servo drive connected properly to your system

Please refer VSD-E datasheet for detailed information about cabling and connections.

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Connecting USB-cable

Servo drive is connected into PC using USB-adapter cable. Cable must be ordered separately and is

only needed for configuring device. Drive is not powered using USB voltage, so logic level power

supply is required for configuring.

Connect USB-cable as shown in figure below.

• Black wire in SPI header pin 1

• Green wire in SPI header pin 6

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Connecting to device

Connecting GDtool to VSD drive should be done by following the given procedure:

1. Start GDtool software from Windows start menu.

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2. Open connection between GDtool and VSD-E servo drive using Device menu Connect to drive

action.

Connection Wizard dialog appears. Follow steps in Wizard dialog.

If VSD drive logic power is on, turn power off. Warning: unless drive already contains working

motor configuration parameters, make sure that HV voltage is also switched off!

Turn servo drive logic power on in step 3.

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Connected dialog should appear. Click Import-button to import drive settings into GDtool GUI.

After a while, default settings should be imported from drive to GDtool interface. If connection is

successful, USB connection icon colour should turn to blue in lower left corner of GDtool window.

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Motor settings

Motor settings page gathers all motor related configurations into single place. Values required for

motor configuration parameters can be found from your motor specifications or documents.

Motor type

Motor type drop-box is used for selecting motor type that is connected into servo drive.

VSD-E servo drive supports following motor types:

• Synchronous AC servo motor (AC) (sinusoidal commutation)

• Brush DC servo motor (DC)

• Synchronous brushless DC motor (BLDC) (trapezoidal commutation)

• Brush DC servo motor (Parallel DC) (parallel wired outputs for higher output current)

• Stepping motor without encoder *

• Stepping motor with encoder *

• Stepping motor with encoder in servo mode (unstallable) *

* These modes are currently under development in VSD-E firmware, see VSD-E manual for details.

Motor phase count (AC, BLDC and Stepper motor)

This is the motor phase count value. Most AC/BLDC motors are 3-phase and most steppers are 2-

phase. In brush DC mode this setting has no effect.

Motor pole count (AC only)

This is the number of magnetic poles in AC servo rotor. In brush DC mode this setting has no

effect.

AC phasing current (AC only)

This is the current that is driven to AC servo windings during power-up to align rotor if motor Hall

sensors are not present or activated (see below). This has no effect in brush DC servo mode.

Max peak current

Maximum peak current output value [mA]. This is DC or peak of sine wave value.

Max continuous current

Maximum continuous current value [mA]. This is DC or peak of sine wave value.

Current fault limit

Sets drive fault current limit. If measured motor current exceeds this value even momentarily, drive

goes into fault state. This should be 1000 to 3000 mA grater than peak current.

Encoder resolution (pulses or lines per revolution)

Sets encoder resolution value to match your motors encoder. Exactly correct value is required for

synchronous motors (all but brush DC). Drive multiplies given resolution by 4 internally, so 500

line encoder equals 2000 counts or steps per rev.

Motor thermal time constant

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This value is motor specific value used for motor thermal overload protection. Use value from

motor specifications or use high value (200 or higher) if unsure.

Invert encoder direction

Inverts encoder counting direction.Use encoder inversion if you are getting follow errors without

any stability. If you encounter lots of troubles with tuning, try toggling this setting.

Use Hall sensors

Enable this option to use motor Hall sensors (AC/BLDC motors only). By using Hall sensors, one

can eliminate the need for AC phasing current allowing instant power-up.

Invert Hall inputs

Digitally inverts Hall sensor inputs.

Configuring motor settings

1. Choose motor settings page

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3. Use drop boxes to choose values for

• Motor type

• Motor pole count (not required for brush DC motors)

• Motor phase count (not required for brush DC motors)

4. Use spin boxes to set current limits values for

• Phasing current (not required for brush DC motors)

• Peak current

• Continuous current

Check you motor specification from motor datasheet or contact your motor supplier if unsure about

correct values.

5. After setting peak and continuous current levels, set current fault limit to from 1000 to 3000

mA higher value than peak current.

6. If encoder is used set pulses per revolution (PPR) value accordingly you encoder specifications.

7. The motor thermal time constant is an indicator of the heat capacity of a motor's windings and

case. Value is used for motor thermal protection. Set value accordingly your motor datasheet.

8. Check/uncheck invert encoder to change encoder direction. Note that there is 50% change that

encoder counting direction doesn't match to motor polarity at the first try. So if you are getting

weird behaviour or total instability, try toggling Invert encoder direction check box. It is

absolutely necessary to set encoder direction correctly to get proper servo operation.

9. If Hall sensors are present and connected (AC/BLDC motors only), check Use Hall sensors

checkbox. You can also invert Hall sensors direction by checking Invert Hall sensors checkbox

Hint: Tool tip is shown by holding mouse over option value a while.

After filling correct values in Motor settings page click Set-button. To apply new motor type

settings drive must be restarted. The Save and reset confirmation dialog should appear. Click Yes-

button to apply settings.

Warning: after this point, drive will start motor control if HV voltage is present! Beware of

unwanted motor motion. Always do the first tests with unconnected motor shaft!

After awhile drive restarts and GDtool software reconnects automatically.

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Test motor configuration

If you are using AC or BLDC motor you can test motor configuration by using Test motor

settings page. Click Test button to test your motor. During test, shaft should start rotating very

slowly.

See VSD-E datasheet for more information about how to connect motor into servo drive if you

encounter any problems.

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General settings

Motor can be controlled using torque, velocity or position mode. Control mode is configured using

Motor control mode radio buttons. Drive controller tuning is introduced in controller Tuning

manual which can be found from GDtool CD or from under Help menu.

Drive pulse input mode There are several ways to send movement commands to drive. Please refer servo drive datasheet for

more detailed information and choose one matching to your system environment.

Motion fault limit

This defines the threshold on how easily drive enters in fault state if motor motion hasn’t been

detected from encoder. This can protect against servo runaways, encoder failures and mechanical

blocking. Value 0 disables this protection.

Voltage limits These are for protecting power supply when drive generates voltage to HV output during motor

braking. Set these values accordingly your power supply maximum output voltage.

Set values accordingly your system settings and press Set-button to apply changes.

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User I/O

User I/Os are several configurable I/O pins in drive. Function for each I/O pin can be configured

using dialog that appears by pressing Configure-button. These settings can be left to default values

if use of user I/O is not required.

Example: to use opto isolated input 4 as disable input, press Configure button in Disable input line

and choose Opto-in 4 from the list. You may change input polarity by checking Inverted checkbox

from the dialog.

Tip: it is useful to configure Disable input and Clear faults in as same physical input (Opto-in 4

for example). This way drive faults are cleared by toggling logic state of opto-in 4.

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Configuring IO pin source

User input and output pins can be configured by using configuration dialog. Outputs can be used

for example showing status information for external motion controller. Output/input states can be

inverted or filtered by selecting option from Options checkboxes.

Some of physical inputs/outputs have also fixed functionality (such as Step/dir input). Fixed

functionality overrides user settings if certain pulse input mode has been selected. See Other

functions column for fixed functions.

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Torque tuning

Torque tuning page is used for setting torque control loop gains and torque low pass filter.

To apply new gain values press Set-button. For more detailed information about evaluating control

loop parameters read control loop Tuning manual.

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Step Response

Servo drive has internal virtual oscilloscope feature which can be used for capturing and storing

several variables or signals with predefined buffer length and sample rate.

Step response page is used for selecting signals, configuring capture buffer length and sample rate.

Step response amplitude value is percentage value of maximum torque command (output current)

value. Press Run step response button for performing step response movement. Note that drive

must be in torque tuning mode for performing torque step response.

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Captures

After valid step response, a plot window appears automatically. Captures window can be also

opened using View menu Show captures action. Captures window is used for plotting capture data

read from servo drive. Capture figures can be loaded, saved and exported in PDF format.

The Index page is for opening capture plots and reverting servo drive settings into GDtool user

interface. Zoom option can be used for checking specific plot areas more accurately.

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Position tuning

In order to tune position mode settings choose and set position mode from General settings page.

There are two position controller modes, PIV and PID.

1. Choose PIV or PID mode using Controller mode drop box

2. Set gain and feedforward values as guided in controller Tuning manual.

3. Set follow error fault trip limit high enough to avoid following error to occur.

4. Configure anti dither settings from Anti-dither page.

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Anti-dither

Anti-dither feature is used for reducing gain values in position mode when motor is holding its

position near final set-point. Setting different gain values reduces motor shaft vibration and noise.

These settings depend on your system configuration and hardware used.

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Position mode step response page is same as in torque tuning mode except Step response amplitude

value is in encoder steps.

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Velocity tuning

Velocity mode should be used when motor rotation speed has to be controlled instead of position or

torque (spindle application for example). Velocity tuning P- and I-gains are same as in position PIV

mode.

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Trajectory planner

Trajectory planner controls drive movement limits. Trajectory planner values can be configured

using numeric up/down boxes and calculated effective values are shown in box bottom of page.

Acceleration limit is the maximum acceleration value that can be used for movements.

Velocity limit is the maximum velocity value that can be used for movements.

Homing acceleration limit is the maximum acceleration value that is used for movements during

homing sequence.

Homing velocity limit is the maximum velocity value that is used for movements during homing.

Error recovery velocity limit is the maximum velocity during error recovery movement. Error

recovering is done after clearing faults.

Absolute position limits can be used for limiting position movement range. Zero value in both

limit boxes disables position limit feature. Note: absolute position limits are active only after

successful homing sequence.

Input scaling is used for fractional scaling or gearing of input commands to another ratio than 1:1.

Scaling works in all input modes (pulse inputs, analog, SPI etc) and in all operation modes

(position, velocity, torque).

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Homing controller

Homing controller can be used in position mode for rotating motor shaft until homing point has

been reached. Homing point can be indicated with following conditions

• Home switch input

• Hard stop (collision detection)

• Encoder index pulse

Homing controller does first the home switch or hard stop search (if enabled) and, after that a index

pulse search (if enabled). Homing can be started at drive power-up or using drive’s input pin to

trigger homing.

Homing hard stop threshold is a following error limit value which triggers home position

detection. Note: when using hard stop detection, be sure to insert at least same value in homing

offset box to avoid motor pushing to mechanical end continuousl (i.e. ensure that axis does not

touch mechanical end after homing to avoid motor heating). Also make sure that follow error trip

limit in Position tuning page is greater than hard stop threshold to avoid triggerint the fault.

Homing offset is used for adjusting position after homing position is detected.

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Note that it’s recommended to test homing function using Test homing button before checking

Start homing after power-up option.

Device Status

Device status page shows the current status of servo drive. Green or Red light is lit if status is

active. Fault registers are marked using red lights and Status register using green lights.

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Active faults can be cleared using Clear faults action from Device menu.

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Device information sub-page shows following information:

• Device type

• Firmware version

• PWM output frequency

• PID loop frequency

• Current position reading of encoder

Encoder value information can be used to check if encoder connection works correctly by rotating

motor shaft manually and by checking encoder value changes according rotation.

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Event Log

Event log page shows information about communication between GDtool GUI and SPIshell

application. Execute shell button can be used for interacting with SPIshell directly.

To see all available commands use List command. Manual usage of shell commands is not required

when tuning servo drive. It’s only option for advanced usage and is not covered by this document.