MMP SA-2550A User manual

MMP SA-2550A
SERVO AMPLIFIER
Description
Power Range
Peak Current 50 A
The MMP SA-2550A PWM servo amplifier is designed to
drive brushed or brushless type DC motors at a high
switching frequency. A single red/green LED indicates
operating status. The drive is fully protected against
over-voltage, under- voltage, over-current, over-heating
and short-circuits across motor, ground and power
leads. Furthermore, the drive can interface with digital
controllers or be used stand-alone, and requires only a
single unregulated DC power supply. Loop gain, current
limit, input gain and offset can be adjusted using 14-
turn potentiometers. The offset adjusting potentiometer
can also be used as an on-board input signal for testing
purposes. This drive can use quadrature encoder inputs,
Hall Sensors, or a tachometer for velocity control.
Continuous Current 25 A
Supply Voltage 20 - 80 VDC
Features
Four Quadrant Regenerative Operation
DIP Switch Selectable Modes
DIP Switch Configurable Loop Tuning
DIP Switch Configurable Current Scaling
DIP Switch Configurable Tachometer
Scaling
Selectable Inhibit Logic
High Switching Frequency
Digital Fault Output Monitor
On-Board Test Potentiometer
Offset Adjustment Potentiometer
Adjustable Input Gain
Selectable 120/60 Hall Commutation Phasing
Encoder Velocity Mode
Hall Velocity Mode
Velocity Monitor Output
Current Monitor Output
Drive Status LED
MODES OF OPERATION
Current
Encoder Velocity
Hall Velocity
Tachometer Velocity
Duty Cycle (Open Loop)
COMMAND SOURCE
±10 V Analog
FEEDBACK SUPPORTED
Hall Sensors
Incremental Encoder
Tachometer (±60 VDC)
MOTORS SUPPORTED
Three Phase (Brushless)
Single Phase (Brushed, Voice Coil, Inductive Load)
COMPLIANCES & AGENCY APPROVALS
UL
cUL
CE Class A (LVD)
CE Class A (EMC)
RoHS II
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Table of Contents
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Information on Approvals and Compliances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
Hardware Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
Importance of Proper Current Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
Using an Encoder Feedback with a Servo Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Running a Brushed DC motor with the Servo Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
Reversing a Brushless Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Regenerative Braking with the Servo Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Loop Tuning Switch Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Mechanical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
Mounting Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Troubleshooting Guide
Red LED Causes and Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
Current Loop Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
Command Curve Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
Servo Amplifier/System Usage Guidelines
When installing a motor, gearmotor, motor control or servo amplifier, universally accepted engineering
practices should always be observed. Please feel free to refer to MMP’s General Tips webpage for general
information regarding proper motor, gearmotor, motor control and servo amplifier usage, to help ensure
proper performance, and complete satisfaction with your application.
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BLOCK DIAGRAM
Note that the above diagram is for a brushless motor with Hall effects and with or without an encoder. If you have purchased other hardware to run
with the amplifier then the above wiring scheme does not apply. Contact MMP for more details.
Information on Approvals and Compliances
US and Canadian safety compliance with UL 508c, the industrial standard for power conversion
electronics. UL registered under file number E140173. Note that machine components compliant
with UL are considered UL registered as opposed to UL listed as would be the case for
commercialproducts.
Compliant with European EMC Directive 2004/108/EC on Electromagnetic Compatibility
(specifically EN 61000-6- 4:2007 for Emissions, Class A and EN 61000-6-2:2005 for Immunity,
Performance Criteria A). LVD requirements of Directive 2006/95/EC (specifically, EN 60204-
1:2004, a Low Voltage Directive to protect users from electrical shock).
The RoHS II Directive 2011/65/EU restricts the use of certain substances including lead, mercury,
cadmium, hexavalent chromium and halogenated flame retardants PBB and PBDE in electronic
equipment.
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SPECIFICATIONS
Description
Power Specifications
Units Value
DC Supply VoltageRange
VDC
20 - 80
DC Bus Over VoltageLimit
VDC
88
DC Bus Under VoltageLimit
VDC
15
Maximum Peak OutputCurrent1
A
50
Maximum Continuous OutputCurrent
A
25
Maximum Continuous Output Power at ContinuousCurrent
W
1900
Maximum Power Dissipation at ContinuousCurrent
W
100
Minimum Load Inductance(Line-To-Line)2
µH
200
Internal Bus Capacitance3
F
75
Low Voltage SupplyOutputs
-
±10 VDC (3 mA), +6 VDC (30 mA), +5 VDC (50 mA)
Switching Frequency
kHz
24
Control Specifications
Description
Units
Value
Command Sources
-
±10 V Analog
Feedback Supported
-
Hall Sensors, IncrementalEncoder, Tachometer (±60 VDC)
Commutation Methods
-
Trapezoidal
Modes ofOperation
-
Current, Encoder Velocity, Hall Velocity, Tachometer Velocity, Duty Cycle (OpenLoop)
Motors Supported
-
Three Phase (Brushless), Single Phase (Brushed, Voice Coil, Inductive Load)
Hardware Protection
-
Over-Current, Over-Temperature, Over-Voltage, Under-Voltage,Short-Circuit
(Phase-Phase & Phase-Ground)
Primary I/O LogicLevel
-
5V TTL
Mechanical Specifications
Description
Units
Value
Agency Approvals
-
CE Class A (EMC), CE Class A (LVD), cUL, RoHS II, UL
Size (H x W x D)
mm (in)
186.73 x 108.8 x 26.9 (7.35 x 4.28 x1.10)
Weight
g (oz)
518 (18.27)
Heatsink (Base) TemperatureRange4
°C (°F)
0 - 65 (32 - 149)
Storage Temperature Range
°C (°F)
-40 - 85 (-40 - 185)
Form Factor
-
Panel Mount
P1 Connector
-
16-pin, 2.54 mm spaced, friction lockheader
P2 Connector
-
5-port, 11.10 mm spaced, screw terminal
P3 Connector
-
5-pin, 5.08 mm spaced, friction lockheader
Notes
1. Maximum duration of peak current is ~2 seconds. Peak RMS value must not exceed continuous current rating of the drive.
2. Lower inductance is acceptable for bus voltages well below maximum. Use external inductance to meet requirements.
3. Minimum additional 470 µF / 100 V external electrolytic capacitor between High Voltage and Power Ground is recommended.
4. Additional cooling and/or heatsink may be required to achieve rated performance.
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PIN FUNCTIONS
P1 - Signal Connector
Pin
Name
Description / Notes
I/O
1
+10V 3mA OUT
±10 V @ 3 mA low power supply for customer use. Short circuit protected. Reference ground
common with signalground.
O
2
SIGNAL GND
GND
3
-10V 3mA OUT
O
4
+REF IN
Differential Reference Input (±10 V Operating Range, ±15 V Maximum Input)
I
5
-REF IN
I
6
-TACH IN
Negative Tachometer Input (Maximum ±60 V). Use signal ground for positive input.
I
7
VEL MONITOR OUT
Velocity Monitor. Analog output proportional to motor speed. In Encoder Velocity mode, output is
proportional to the encoder line frequency. Encoder Velocity scaling is 22 kHz/V. In Hall Velocity mode,
output is proportional to the Hall frequency. Hall Velocity scaling is 100 Hz/V.
O
8
CURR MONITOR OUT
Current Monitor. Analog output signal proportional to the actual current output. Scaling is 8.05 A/V by
default but may be reduced by half this value by setting DIP switch SW1-3 to OFF (see Hardware
Setting section below). Measure relative to power ground.
O
9
INHIBIT /ENABLE
TTL level (+5 V) inhibit/enable input. Pull to ground to inhibit drive (SW1-2 ON). Pull to ground
to enable drive (SW1-2 OFF). Inhibit turns off all power devices.
I
10
+V HALL 30mA OUT
Low Power Supply For Hall Sensors (+6 V @ 30 mA). Referenced to signal ground. Short circuit
protected.
O
11
GND
Signal Ground
GND
12
HALL 1
Single-ended Hall/Commutation Sensor Inputs (+5 V logiclevel). Leave open for brushed motors.
I
13
HALL 2
I
14
HALL 3
I
15
CURR REF OUT
Measures the command signal to the internal current-loop. This pin has a maximum output of
±7.25 V when the drive outputs maximum peak current. Measure relative to power ground.
O
16
FAULT OUT
TTL level (+5 V) output becomes high when power devices are disabled due to at least one of the
following conditions: inhibit, invalid Hall state, output short circuit, over voltage, over temperature,
power-upreset.
O
P2 - Power Connector
Pin
Name
Description / Notes
I/O
1
A
Motor Phase A
O
2
B
Motor Phase B
O
3
C
Motor Phase C
O
4
POWER GND
Power Ground (Common With SignalGround)
PGND
5
HIGHVOLTAGE
DC Power Input
I
P3 –Feedback Connector
Pin
Name
Description / Notes
I/O
1
+5V
Low Power Supply for Encoder (+5V). Internally connected to P1-10. Total current available from P3-1
to P1-10 is 150 mA. Referenced to signal ground. Sort circuit protected.
O
2
CHANNEL A
Single-ended encoder channel A input. +5 V logic level.
I
3
NC
Not Connected (Reserved)
-
4
CHANNEL B
Single-ended encoder channel B input. +5 V logic level.
I
5
SIGNAL GND
Signal Ground
SGND
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HARDWARE SETTINGS
Configuration Switch Functions
SW1
Description
Setting
On
Off
1
Duty Cycle mode selector. Activates internal PWMfeedback.
Duty Cycle mode
Other modes
2
Inhibit logic. Sets the logic level of inhibitpins.
Drive Inhibit is active low
Drive Inhibit is active high
3
Test/Offset. Switches the function of the Test/Offset potbetween
an on-board command input for testing or a commandoffset
adjustment. OFF bydefault.
Test
Offset
4
Outer loop integration. Activates or deactivates integration.ON,
by default, for current mode and OFF for othermodes.
Inactive
Active
5
Mode Selection. See mode selection table below.
-
-
6
-
-
7
Velocity feedback polarity. Changes the polarity of theinternal
feedback signal and the velocity monitor output signal. Inversion
of the feedback polarity may be required to prevent a motorrun-
away condition.
Standard
Inverted
8
Mode Selection. See mode selection table below.
-
-
9
Reserved
-
-
10
60/120 degree commutation phasingsetting
120 degrees
60 degrees
Mode Selection Table
SW1-4
SW1-5
SW1-6
SW1-8
Tachometer
CURRENT
ON
OFF
OFF
ON
Not Connected
DUTY CYCLE
OFF
ON
OFF
OFF
Not Connected
ENCODER VELOCITY
OFF
OFF
OFF
OFF
Not Connected
HALL VELOCITY
OFF
OFF
ON
OFF
Not Connected
TACHOMETER VELOCITY
OFF
OFF
OFF
OFF
Connected
SW2
Description
Setting
On
Off
1
Tachometer Input Voltage Scaling. Adjusts the maximum range of
the tachometer input.
Max tachometer input values from 5V to 61V. See
Maximum Tachometer Input Voltage Table below.
2
3
4
Configures the drive to output either peak and continuous
current values, or continuous current only.
Peak and Continuous Current
Continuous Current Only
Maximum Tachometer Input Voltage Table
Default switch settings are shaded.
Switch
Maximum Tachometer Input Voltage (±VDC)
61
53
45
37
29
21
13
5
SW2-1
OFF
ON
OFF
ON
OFF
ON
OFF
ON
SW2-2
OFF
OFF
ON
ON
OFF
OFF
ON
OFF
SW2-3
OFF
OFF
OFF
OFF
ON
ON
ON
ON
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(Note : Drive cover must be removed to access SW4)
SW4
Description
Setting
1
Advanced Tuning
(Velocity Loop Integrator Capacitance)
See SW4 table in Loop Tuning Switch Functions section for
switch settings and corresponding capacitance values.
2
3
4
5
Continuous Current Scaling. Configures the drive to set the
continuous current limit at a percentage of the drive peak
current limit.
See Continuous Current Scaling Table below for switch
settings and corresponding values.
6
7
8
Peak and Continuous Current Scaling. Adjusts both the peak
and continuous drive current limits.
See Peak and Continuous Current Scaling Table below for
switch settings and corresponding values.
9
10
Continuous Current Scaling Table
Default switch settings are shaded.
Switch
Continuous Current Scaling (% of Peak Current)
50
43.6
37.6
31.6
25.6
19.7
13.7
7.75
SW4-5
OFF
ON
OFF
ON
OFF
ON
OFF
ON
SW4-6
OFF
OFF
ON
ON
OFF
OFF
ON
ON
SW4-7
OFF
OFF
OFF
OFF
ON
ON
ON
ON
Peak and Continuous Current Scaling Table
Default switch settings are shaded.
Switch
Peak and Continuous Current Scaling* (APEAK)
50
43.63
38.60
34.61
31.37
28.67
26.40
24.47
SW4-8
OFF
ON
OFF
ON
OFF
ON
OFF
ON
SW4-9
OFF
OFF
ON
ON
OFF
OFF
ON
ON
SW4-10
OFF
OFF
OFF
OFF
ON
ON
ON
ON
Potentiometer Functions
Potentiometer
Description
Turning CW
1
Loop gain adjustment for duty cycle / velocity modes. Turn thispot
fully CCW in current mode.
Increases gain
2
Current limit. It adjusts both continuous and peak currentlimit
while maintaining their ratio.
Increases limit
3
Reference gain. Adjusts the ratio between input signal andoutput
variables (voltage, current, orvelocity).
Increases gain
4
Offset / Test. Used to adjust any imbalance in the input signal orin
the amplifier. Can also be used as an on-board signal sourcefor
testing purposes.
Adjusts offset in negativedirection
Note: Potentiometers are approximately linear and have 12 active turns with 1 inactive turn on each end. Test points are provided on the drive PCB near each
potentiometer to measure the potentiometervalue.
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Importance of Proper Current Monitoring
There are many factors which affect motor performance and longevity. One very important factor to motor life is motor current. An
input current that is too high can cause severe, irreversible damage to a motor. One common misconception with servo amplifiers is
that the input current into the amplifier and output current to the motor phases are the same amplitude:
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Due to the nature of the MMP SA-2550A the input and output currents usually correlate but are not always equal. To ensure the
motor is receiving the proper amount of current we highly recommend utilizing the current monitor pin (P1-8, see page 5, Pin
Functions table for further details) and measuring the voltage relative to signal ground as shown below.
The voltage output is analog and linearly scaled to the current input to the motor phases. The scale is 8.05 A/V by default as stated
in the Pin Functions table on page 5.
The current monitor signal tracks current delivered to all three motors phases (where applicable).
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Using an Encoder Feedback with a Servo Amplifier
Encoders can be used with the MMP SA-2550A to provide feedback to the amplifier and control speed of the motor. The default
setting on the servo amplifier is duty cycle mode. This mode does not use motor feedback. If motor speed as feedback is required
then using an encoder as feedback to the Servo Amplifier is recommended. For encoder feedback the MMP SA-2550A needs to be
properly configured and wired.
The resolution of the encoder and speed of the motor is important for proper speed control. The MMP SA-2550A uses both
parameters to input a switching frequency and thus control the motor speed. The MMP SA-2550A has a maximum switching
frequency of 24 kHz (Specifications table, page 4). As long as the input frequency is no less than 10 Hz and does not exceed the
maximum frequency the servo amplifier is able to control speed smoothly. Typically an encoder resolution is chosen that maximizes
the input frequency without exceeding the switching frequency. The encoder resolution is also chosen based on the following
guidelines for expected maximum motor speed:
Maximum Motor Speed (RPM)
Encoder Resolution (Counts per Revolution)
Greater Than
Less Than
Greater Than
Less Than
2500
500
2500
5000
250
500
5000
10000
100
250
10000
100
To utilize encoder feedback ensure the SW1 switches are configured as specified on page #.
As shown below, ensure the encoder, potentiometer and external encoder source are grounded. Note that the encoder must be
powered by an external source (usually 5 VDC). If the encoder channels are double ended then use the positive signal of each
channel (labeled A+ and B+ on the below figure) as the feedback signal to the servo amplifier.
Figure 1. Encoder feedback wiring with potentiometer command.
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If an external command signal (usually 10 VDC) is used in place of a potentiometer then wire as shown below. Remove connection to
P1-1 and connect the signal positive to pin 5 (for %0-%100 POT effect). Ensure VCOM is grounded to P1-2.
Figure 2. Encoder feedback with external command.
For further details on configuring the command signal curve, please consult the answer to question 3 in the troubleshooting guide,
found on page 22.
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Running a Brushed Motor with a Brushless Drive
Follow the below steps to configure a SA-2550A to run a brushed, DC motor.
Switch Setting
Set the 120°/60° PHASING dipswitch to OFF for 60° phasing. For the SA-2550A this is SW 1-10. The OFF position is toward the
outside of the servo amplifier as shown in the picture below.
Note: Make sure to disconnect all Hall sensor inputs.
Figure 1. 120°/60° Phasing Switch Example
Motor Connections
With the 120°/60° PHASING switch OFF, the motor connections to the servo drive will be to the MOTOR A and MOTOR B
terminals only.
Terminal
Connection
MOTOR A
Negative (-)
MOTOR B
Positive (+)
MOTOR C
No Connection
Table 1. Brushed Motor Connections. Note that the above assumes the polarity of the 10V @3mA and REF leads for the
command signal to be opposite. Consult the second table on page 12 for further details.
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How to reverse a brushless DC motor
Figure 2. Typical Wiring Solution of a Brushless Motor with Encoder.
The typical wiring solution shown above results in the brushless motor to run forward (CW rotation) with the potentiometer max at
the CW position. Methods to reverse the brushless motor direction via wiring are as follows:
-Change the wiring connections of the potentiometer or jump leads. There are many ways to wire a potentiometer to the
servo amplifier or jump the potentiometer leads. Consult the tables below for what leads to connect to which pins.
Potentiometer Wiring Solutions
Connect Potentiometer Leads to Pins
Motor Direction
of Rotation*
Potentiometer
RED (+5V)
BLK (GND)
WHT (WIPER)
Range
Rotation
P1-1
P1-2
P1-5
FWD
0-100%
CW
P1-3
P1-2
P1-4
FWD
0-100%
CW
P1-1
P1-2
P1-4
REV
0-100%
CW
P1-3
P1-2
P1-5
REV
0-100%
CW
P1-2
P1-3
P1-4
FWD
100-0%
CCW
P1-2
P1-1
P1-5
FWD
100-0%
CCW
P1-2
P1-1
P1-4
REV
100-0%
CCW
P1-2
P1-3
P1-5
REV
100-0%
CCW
*Assumes that Hall Sensors and Motor Leads are wired in accordance with the above diagram.
Wire without Potentiometer (direct pin connections)
Connect Leads
Motor Direction
of Rotation*
Simulated
Potentiometer Output
P1-1
P1-5
FWD
100%
P1-3
P1-4
FWD
100%
P1-1
P1-4
REV
100%
P1-3
P1-5
REV
100%
*Assumes that Hall Sensors and Motor Leads are wired in accordance with the above diagram.
-Change Motor and Hall Sensor Leads. To reverse motor direction, consult the below table to properly change motor and hall
sensor leads.
Motor
Direction
Hall Sensor Connection to Drive
Motor Connection to Drive
H1 (BLU)
H2 (GRY)
H3 (VLT)
M1 (RED)
M2 (BLK)
M3 (WHT)
FWD
P1-12
P1-13
P1-14
P2-1
P2-2
P2-3
REV
P1-14
P1-13
P1-12
P2-2
P2-1
P2-3
WARNING : DO NOT reverse the servo amplifier input power leads, HV (P2-5) and GND (P2-4) to reverse the direction of motor
rotation. This can cause severe, irreversible damage to the servo amplifier.
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Regenerative braking with the SA-2550A
Regeneration and Shunt Regulators
Use of a shunt regulator is necessary in systems where motor deceleration or a downward motion of the motor load will cause the
system’s mechanical energy to be regenerated via the drive back onto the power supply.
I
Torque +
Velocity +
No Regen
II
Torque -
Velocity +
Regen
III
Torque -
Velocity -
No Regen
IV
Torque +
Velocity -
Regen
Figure 3. Four Quadrant Operation –Regeneration occurs when Torque and Velocity are opposite.
This regenerated energy can charge the power supply capacitors to levels above that of the drive over-voltage shutdown level. If the
power supply capacitance is unable to handle this excess energy, or if it is impractical to supply enough capacitance, then an external
shunt regulator must be used to dissipate the regenerated energy. Shunt regulators are essentially a resistor placed in parallel with
the DC bus. The shunt regulator will "turn-on" at a certain voltage level (set below the drive over-voltage shutdown level) and
discharge the regenerated electric energy in the form of heat.
The voltage rise on the power supply capacitors without a shunt regulator, can be calculated according to a simple energy balance
equation. The amount of energy transferred to the power supply can be determined through:

Where
Initial Energy
Final Energy
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These energy terms can be broken down into the approximate mechanical and electrical terms - capacitive, kinetic, and potential
energy. The energy equations for these individual components are as follows:







–Energy stored in capacitor (J)
C–Capacitance (F)
 –Nominal bus voltage of the system
–mechanical energy of the load (J)
J–moment of inertia of the load (kg-m2)
–angular velocity of the load (rad/s)
–potential energy of load (J)
m–mass of the load (kg)
g–gravitational acceleration (9.81 m/s2)
h–vertical height of the load (m)
During regeneration the kinetic and potential energy will be stored in the power supply’s capacitor. To determine the final power
supply voltage following a regenerative event, the following equation may be used for most requirements:




  

Which simplifies to:





The Vfcalculated must be below the power supply capacitance voltage rating and the drive over voltage limit. If this is not the case,
a shunt regulator is necessary. A shunt regulator is sized in the same way as a motor or drive, i.e. continuous and RMS power
dissipation must be determined. The power dissipation requirements can be determined from the application move profile.
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Figure 4. Example of motor profile during operation.
When choosing a shunt regulator, select one with a shunt voltage that is greater than the DC bus voltage of the application but less
than the over voltage shutdown of the drive. Verify the for a shunt regulator by operating the servo drive under the worst-case
braking and deceleration conditions. If the drive shuts off due to over-voltage, a shunt regulator is necessary.
Continuous Regeneration
In the special case where an application requires continuous regeneration (more than a few seconds) then a shunt regulator may not
be sufficient to dissipate the regenerative energy. Some examples include:
Web tensioning device
Electric vehicle rolling down a long hill
Spinning mass with a very large inertia (grinding wheel, flywheel, centrifuge)
Heavy lift gantry
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Loop Tuning Switch Functions
In general, the drive will not need to be further tuned beyond the default configuration. However, for applications requiring more
precise tuning, DIP switches can be used to adjust the current and velocity loop tuning values. Some general rules of thumb to
follow when tuning the drive are:
A larger resistor value will increase the proportional gain, and therefore create a faster response time.
A larger capacitor value will increase the integration time, and therefore create a slower response time.
Proper tuning will require careful observation of the loop response on a digital oscilloscope to find optimal DIP switch settings for
the specific application.
(Note: Drive cover must be removed to access SW3 and SW4)
SW3 DIP switches add additional resistance and capacitance to the current loop tuning circuitry. SW3 switches 1-5 add
additional series resistance to the current loop gain resistor, and SW3 switches 6-10 add additional parallel capacitance to the
current loop integrator capacitor (see Block Diagram). The resulting capacitance and resistance values are given in the tables
below along with the appropriate DIP switch settings. The default switch settings are shaded in the SW3 tables below.
SW3
Switch
Current Loop Proportional Gain Resistance Options (k)
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
SW3-1
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
SW3-2
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
SW3-3
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
SW3-4
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
SW3-5
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
Switch
(continued
)
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
SW3-1
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
SW3-2
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
SW3-3
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
SW3-4
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
SW3-5
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
SW3
Current Loop Integrator Capacitance Options (  F)
Switch
.0047
.0094
.0247
.0294
.0517
.0564
.0717
.0764
.0987
.1034
.1187
.1234
.1457
.1504
.1647
.1694
SHORT
SW3-6
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
SW3-7
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
ON
SW3-8
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
SW3-9
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
SW3-10
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
SW4 DIP switches 1-4 add additional parallel capacitance to the velocity loop integrator capacitor. The resulting capacitance values
are given in the table below along with the appropriate DIP switch settings. The default switch settings are shaded in the SW4 table
below.
SW3
Current Loop Integrator Capacitance Options (  F)
Switch
.0047
.0094
.0247
.0294
.0517
.0564
.0717
.0764
.0987
.1034
.1187
.1234
.1457
.1504
.1647
.1694
SHORT
SW4-1
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
SW4-2
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
ON
SW4-3
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
SW4-4
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
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MECHANICAL INFORMATION
P1 - Signal Connector
ConnectorInformation
16-pin, 2.54 mm spaced, friction lockheader
Mating Connector
Details
Molex: P/N 22-01-3167 (connector) and P/N 08-50-0114 (insertterminals)
Included with Drive
Yes
15 VEL MONITOR OUT
13 HALL 2
11 GND
9 INHIBIT/ENABLE
7 ENCODER-A IN
5 -REF IN
3 -10V 3mA OUT
1 +10V 3mA OUT
2 SIGNAL GND
4 +REF IN
6 ENCODER-B IN
8 CURRENT MONITOR
10 +V HALL 30mA OUT
12 HALL 1
14 HALL 3
16 FAULT OUT
P2 - Power Connector
ConnectorInformation
5-port, 11.10 mm spaced, screwterminal
Mating Connector
Details
N/A
Included with Drive
N/A
P3 - Feedback Connector
ConnectorInformation
5-port, 5.08 mm spaced, quick-disconnectterminal
Mating Connector
Details
Molex: P/N 22-01-3057 (connector) and P/N 08-50-0114 (insertterminals)
Included with Drive
Yes
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MOUNTING DIMENSIONS
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TROUBLESHOOTING GUIDE
Below are covered common questions and issues related to the SA-2550A servo amplifier.
1. What a red LED indicator means and how to fix it.
2. How to perform current loop tuning on the SA-2550A.
3. Adjusting the Command Signal Curve using the built in potentiometers of the SA-2550A servo amplifier.
1. Red LED indicator meaning and methods of correction
A red LED can indicate any of the following fault conditions:
Over-voltage
Under-voltage
Invalid Hall State
Drive Inhibited
Over-temperature
Short circuit
Over-current
Power-on Reset
Fault conditions are non-latching, meaning that when the fault condition is removed, the drive will enable (green LED).
Troubleshooting Instructions
1. Remove all connections from the drive. This includes the voltage supply, motor power cables, feedback and any controller I/O.
2. For a brushed drive, configure the amplifier for voltage mode. For a brushless drive, configure the amplifier for open loop
mode. The switch settings for each mode can be found on the drive datasheet.
3. If using a brushless drive, set the 60 / 120 phasing switch to 60 degrees, which is the OFF position.
4. Apply power to the drive. If the drive has inverted inhibits, short the master inhibit pin to signal ground (for more information
on inverted inhibits, see Drive Inhibited section). The LED should be green. The drive will fault if too much or too little
voltage is applied to the drive. See Over-voltage and Under-Voltage section for details on this fault condition.
5. Remove power from the drive. If using a brushless motor, connect Hall sensor inputs and set the 60 / 120 phasing switch to
the correct position according to the motor. Apply power to the drive and rotate the motor by hand. If the LED is red or
changing between red and green, this could indicate an issue with the Hall sensor inputs. See Invalid Hall State section for
details on this fault condition. Note: Most motors have 120 degree Hall sensors.
6. Remove power from the drive and connect motor power cables. Set the Test/Offset switch to the OFF position and set POT4,
the Test/Offset pot, 7 turns from the full clockwise direction.
7. Apply power. If the LED is red, it could be an indication of a short circuit fault. See Short Circuit section for details on this
fault condition.
8. Remove power and connect the controller. Remove any command from the controller to avoid unexpected motion in the motor.
9. Apply power. If the LED is red, check if the controller is disabling the drive. See Drive Inhibited section for more information
about the inhibit input.
Fault Conditions Explained
Over-voltage and Under-voltage
An over-voltage fault occurs when the bus voltage exceeds the over-voltage limit of the drive. An under-voltage can occur if too
little voltage is applied to the drive. The voltage rating can be found on the drive datasheet.
For DC input drives, verify that the DC input voltage is within the spec of the drive.
For AC input drives, verify that the AC input voltage is within the spec of the drive.
Regeneration
If the drive faults during a deceleration or when lowering a vertical load, it could be due to regeneration energy raising the bus
voltage beyond its over-voltage limit.
During these types of moves, the system’s mechanical energy gets converted into electrical energy that flows back onto the DC
bus. This charges the capacitors in the power supply and raises the DC bus voltage.
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A shunt regulator may be necessary to dissipate the energy regenerated by the system. See the section on regenerative braking,
pages 13-15 for more details.
Invalid Hall State
Brushless drives have 3 Hall sensor inputs that determine a Hall state. The drive will fault if an invalid Hall state is detected.
If the LED is red or changing between red and green as the motor rotates, it could be an indication of an invalid Hall state.
Connect only the Hall sensors to the drive and apply power.
Make sure the 60 or 120 phasing switch is in the correct position according to motor.
Verify that all Hall sensor inputs are wired correctly to the drive.
Measure the voltage levels for all Hall sensor inputs. The voltage levels should change between 0 and 5V as the motor rotates.
If using a motor with both Hall sensors and an encoder, make sure the supply for the feedback has enough power. Drives with
onboard Hall sensor power rated at 30mA won’t have enough current and a separate supply will be required.
If using a separate supply for the Hall sensors, make sure the ground reference for the supply is tied to the signal ground of
the drive.
Rotate the motor and verify that ALL Hall sensor inputs are changing and follow the Hall sequence in the table below.
60 Degree 120 Degree
60 Degree
120 Degree
Hall A
Hall B
Hall C
Hall A
Hall B
Hall C
1
0
0
1
0
0
1
1
0
1
1
0
1
1
1
0
1
0
Valid
0
1
1
0
1
1
Green
0
0
1
0
0
1
LED
0
0
0
1
0
1
1
0
1
1
1
1
Invalid Red
0
1
0
0
0
0
LED
Table 1. Valid and invalid hall sensor states per brushless motor phase.
1 –Indicates high level hall sensor input (5V)
0 –Indicates low level hall sensor input (0V)
Drive Inhibited
For standard inhibits, the drive disables when the inhibit pin is grounded. For inverted inhibits, the drive enables when the inhibit
pin grounded.
A drive with standard inhibits has a 0 ohm SMT resistor labeled “J1” installed on the PCB. Removing this jumper will invert the
inhibits. Amplifiers can be ordered with the J1 jumper removed and have a “-INV” on the end of the part number, e.g., 12A8-INV.
Some drives have a DIP switch to invert the inhibits. This option will be listed on the drive datasheet if available.
Note: Some drives have directional inhibits (+INHIBIT / -INHIBIT) which inhibit motion in their respective directions but do NOT
cause a red LED.
Measure the voltage of the inhibit pin. It should read 5V if left open and 0 if grounded.
Verify if the drive is configured for standard or inverted inhibits.
If your controller is disabling the drive, verify under what conditions this will occur, e.g., position following error, position limit
reached, etc.
Over-temperature
The drive will fault if the heat sink base plate temperature exceeds 65C.
Safely measure the heat sink base plate temperature.
If the temperature exceeds 65C, additional cooling may be necessary.
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