LICHUAN MC856 User manual

Instruction Book
for
MC856
High Performance Microstepping Driver
18-80VDC / 6A

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CATALOG
1. Introduction............................................................................................................... 2
◆Introduction......................................................................................................... 2
◆Features................................................................................................................2
◆Applications..........................................................................................................2
2. Specifications............................................................................................................. 2
◆Electrical Specifications (Tj = 25℃/77℉)........................................................ 2
◆Operating Environment....................................................................................... 2
◆Installation specifications (unit: mm [inch])....................................................3
◆Elimination of Heat.............................................................................................. 3
3. External terminal instructions...................................................................................3
◆Control Signal Connector.....................................................................................3
◆Main Circuit Connector........................................................................................3
4. Control Signal Connector Interface........................................................................... 4
◆Typical Connection...............................................................................................4
◆Sequence Chart of Control Signals...................................................................... 5
5. Connecting the Motor................................................................................................5
◆Connections to 4-lead Motors.............................................................................5
◆Connections to 8-lead Motors.............................................................................5
6. Power Supply Selection............................................................................................. 6
◆Regulated or Unregulated Power Supply............................................................6
◆Multiple Drivers................................................................................................... 6
◆Selecting Supply Voltage..................................................................................... 6
7. Selecting Microstep Resolution and Output Current............................................... 6
◆Microstep Resolution Selection.......................................................................... 7
◆Current Settings................................................................................................... 7
◆Standstill current setting..................................................................................... 7
8. Wiring Notes.............................................................................................................. 8
9. Protection Functions..................................................................................................8
Over-current Protection............................................................................................ 8
Over-voltage Protection............................................................................................ 8
Hase Error Protection................................................................................................ 8
10. Frequently Asked Questions....................................................................................8

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1. Introduction
◆Introduction
MC856 is a kind of digital low-voltage stepper motor drive, using the latest 32-bitDSP
technology, suitable for 57, 86 series motor,have good performance at low speed.
Arbitrary subdivision and any current value can be set within 256 or the rated current, it
can meet the needs of the most small equipment applications.Using built-in micro
technology, even under the condition of low breakdown, can achieve high segmentation
effect, low operation is very stable, with low noise.
◆Features
·Supply voltage up to +80VDC;
·Output current programmable, from 2.4A to7.2A;
·Pulse input frequency200KHz;
·16 selectable resolutions up to 51,200 steps/rev;
·TTL compatible and optically isolated input;
·Pure-sinusoidal current control technology;
·Self-adjustment technology;
·Support PUL/DIR;
·Short-voltage, over-voltage, over-current protections;
·Automatic idle-current reduction.
◆Applications
Suitable for a wide range of stepping motors, from NEMA size 17 to 43. It can be used in
various kinds of machines, such as X-Y tables, labeling machines, laser cutters, engraving
machines,pick-place devices, and so on. Particularly adapt to the applications desired
with low noise, low heating, high speed performance.
2. Specifications
◆Electrical Specifications (Tj = 25℃/77℉)
Parameters
Min
Typical
Max
Output current
2.4A
7.2 A
Supply voltage
+20VDC
+48VDC
+80VDC
Logic signal current
7mA
10 mA
16 mA
Pulse input frequency
0
200 kHz
Isolation resistance
500 MΩ
◆Operating Environment
Environment
Avoid dust, oil fog and corrosive gases
Ambient Temperature
0℃ － 50℃
Humidity
40%RH －90%RH
Operating Temperature
70℃Max
Vibration
5.9m/s2 Max
Storage Temperature
-20℃ － 65℃

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◆Installation specifications (unit: mm [inch])
Figure 1: Installation specifications
◆Elimination of Heat
·Driver’s reliable working temperature should be <70℃(158℉), and motor working
temperature should be <80℃(176℉);
·It is recommended to use automatic idle-current mode, namely current automatically
reduce to 60% when motor stops, so as to reduce driver heating and motor heating;
·It is recommended to mount the driver vertically to maximize heat sink area. Use
forced cooling method to cool the system if necessary.
3. External terminal instructions
◆Control Signal Connector
Pin Function
Details
PUL+
Pulse signal: In single pulse (pulse/direction) mode, this input represents
pulse signal, each rising or falling edge active; 4-5V when PUL-HIGH,
0-0.5V when PUL-LOW. For reliable response, pulse width should be longer
than 1.5μs. Series connect resistors for current-limiting when +12V or
+24V used. The same as DIR and ENA signals.
PUL-
DIR+
DIR signal: In single-pulse mode, this signal has low/high voltage levels,
representing two directions of motor rotation; For reliable motion
response, DIR signal should be ahead of PUL signal by 5μs at least.
4-5V when DIR-HIGH, 0-0.5V when DIR-LOW. Please note that rotation
direction is also related to motor-driver wiring match. Exchanging the
connection of two wires for a coil to the driver will reverse motion
direction.
DIR-
ENA+
Enable signal: This signal is used for enabling/disabling the driver. High
level (NPN control signal, PNP and Differential control signals are on the
contrary, namely Low level for enabling.) for enabling the
driver and low level for disabling the driver. Usually left
UNCONNECTED (ENABLED).
ENA-
◆Main Circuit Connector
Pin Function
Details
+V
Power supply, 20~80 VDC, Including voltage fluctuation and EMF voltage.
GND
Power Ground.
A+, A-
Motor Phase A
B+, B-
Motor Phase B

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4. Control Signal Connector Interface
The MC856 can accept differential and single-ended inputs (including open-collector and
PNP output). The MC856 has 3 optically isolated logic inputs which are located on
connector P1 to accept line driver control signals. These inputs are isolated to minimize
or eliminate electrical noises coupled onto the drive control signals. Recommend use line
driver control signals to increase noise immunity of the driver in interference
environments. In the following figures, connections to open-collector and PNP signals are
illustrated.
Figure 2: Connections to open-collector signal (common-anode)
Figure 3: Connection to PNP signal (common-cathode)
◆Typical Connection
A complete stepping system should include stepping motor, stepping driver, power
supply and controller (pulse generator). A typical connection is shown as figure 4.
Figure 4: Typical connection

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◆Sequence Chart of Control Signals
In order to avoid some fault operations and deviations, PUL, DIR and ENA should abide
by some rules, shown as following diagram:
Figure 5: Sequence chart of controlsignals
Remark:
·t1: ENA must be ahead of DIR by at least 5 ms. Usually, ENA+ and ENA- are NC (not
connected). See “Connector P1 Configurations”for more information.
·t2: DIR must be ahead of PUL effective edge by 5m s to ensure correct direction;
·t3: Pulse width not less than 1.5m s;
·t4: Low level width not less than 1.5m s.
5. Connecting the Motor
The MC856 can drive any 2-pahse and 4-pahse hybrid stepping motors.
◆Connections to 4-lead Motors
4 lead motors are the least flexible but easiest to wire. Speed and torque will depend on
winding inductance. In setting the driver output current, multiply the specified phase
current by 1.4 to determine the peak output current.
Figure 6: 4-lead MotorConnections
◆Connections to 8-lead Motors
8 lead motors offer a high degree of flexibility to the system designer in that they may be
connected in series or parallel, thus satisfying a wide range of applications.
·Series Connections
A series motor configuration would typically be used in applications where a higher
torque at lower speeds is required. Because this configuration has the most inductance,
the performance will start to degrade at higher speeds. In series mode, the motors
should also be run at only 70% of their rated current to prevent over heating.
Figure 7: 8-lead motor seriesconnections

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6. Power Supply Selection
The MC856 can match medium and small size stepping motors (from NEMA frame size
17 to 34) made by Lichuan or other motor manufactures around the world. To achieve
good driving performances, it is important to select supply voltage and output current
properly. Generally speaking, supply voltage determines the high speed performance of
the motor, while output current determines the output torque of the driven motor
(particularly at lower speed). Higher supply voltage will allow higher motor speed to be
achieved, at the price of more noise and heating. If the motion speed requirement is low,
it’s better to use lower supply voltage to decrease noise, heating and improve reliability.
◆Regulated or Unregulated Power Supply
Both regulated and unregulated power supplies can be used to supply the driver.
However, unregulated power supplies are preferred due to their ability to withstand
current surge. If regulated power supplies (such as most switching supplies.) are indeed
used, it is important to have large current output rating to avoid problems like current
clamp, for example using 4A supply for 3A motor-driver operation. On the other hand, if
unregulated supply is used, one may use a power supply of lower current rating than that
of motor (typically 50%～70% of motor current). The reason is that the driver draws
current from the power supply capacitor of the unregulated supply only during the ON
duration of the PWM cycle, but not during the OFF duration. Therefore, the average
current
withdrawn from power supply is considerably less than motor current. For example, two
3A motors can be well supplied by one power supply of 4A rating.
◆Multiple Drivers
It is recommended to have multiple drivers to share one power supply to reduce cost, if
the supply has enough capacity. To avoid cross interference, DO NOT daisy-chain the
power supply input pins of the drivers. (Instead, please connect them to power supply
separately.)
◆Selecting Supply Voltage
The power MOSFETS inside the MC856 can actually operate within 20~80VDC, including
power input fluctuation and back EMF voltage generated by motor coils during motor
shaft deceleration. Higher supply voltage can increase motor torque at higher speeds,
thus helpful for avoiding losing steps. However, higher voltage may cause bigger motor
vibration at lower speed, and it may also cause over-voltage protection or even driver
damage. Therefore, it is suggested to choose only sufficiently high supply voltage for
intended applications, and it is suggested to use power supplies with theoretical output
voltage of +20 ~ +80VDCleaving room for power fluctuation and back-EMF.
7. Selecting Microstep Resolution and Output Current
This driver uses an 8-bit DIP switch to set microstep resolution, and motor operating
current, as shown below:

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◆Microstep Resolution Selection
Microstep resolution is set by SW5, 6, 7, 8 of the DIP switch as shown in the following
table:
Microstep
Steps/rev.(for 1.8 ° motor)
SW5
SW6
SW7
SW8
2
400
ON
ON
ON
ON
4
800
OFF
ON
ON
ON
8
1600
ON
OFF
ON
ON
16
3200
OFF
OFF
ON
ON
32
6400
ON
ON
OFF
ON
64
12800
ON
OFF
OFF
ON
128
25600
OFF
OFF
OFF
ON
256
51200
OFF
OFF
OFF
ON
5
1000
ON
ON
ON
OFF
10
2000
OFF
ON
ON
OFF
20
4000
ON
OFF
ON
OFF
25
5000
OFF
OFF
ON
OFF
40
8000
ON
ON
OFF
OFF
50
10000
OFF
ON
OFF
OFF
100
20000
ON
OFF
OFF
OFF
200
40000
OFF
OFF
OFF
OFF
◆Current Settings
For a given motor, higher driver current will make the motor to output more torque, but
at the same time causes more heating in the motor and driver. Therefore, output current
is generally set to be such that the motor will not overheat for long time operation. Since
parallel and serial connections of motor coils will significantly change resulting
inductance and resistance, it is therefore important to set driver output current
depending on motor phase current, motor leads and connection methods. Phase current
rating supplied by motor manufacturer is important in selecting driver current, however
the selection also depends on leads and connections.
The first three bits (SW1, 2, 3) of the DIP switch are used to set the dynamic current.
Select a setting closest to your motor’s required current.
Peak Current
RMS Current
SW1
SW2
SW3
2.40A
2.00A
ON
ON
ON
3.08A
2.57A
OFF
ON
ON
3.77A
3.14A
ON
OFF
ON
4.45A
3.71A
OFF
OFF
ON
5.14A
4.28A
ON
ON
OFF
5.83A
4.86A
OFF
ON
OFF
6.52A
5.43A
ON
OFF
OFF
7.20A
6.00A
OFF
OFF
OFF
Notes: Due to motor inductance, the actual current in the coil may be smaller than the
dynamic current setting, particularly under high speed condition.
◆Standstill current setting
SW4 is used for this purpose. OFF meaning that the standstill current is set to be half of
the selected dynamic current, and ON meaning that standstill current is set to be the
same as the selected dynamic current.
The current automatically reduced to 60% of the selected dynamic current one second
after the last pulse. Theoretically, this will reduce motor heating to 36% (due to P=I2*R)
of the original value. If the application needs a different standstill current, please contact
Lichuan.

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8. Wiring Notes
In order to improve anti-interference performance of the Driver, it is recommended
to use twisted pair shield cable.
To prevent noise incurred in PUL/DIR signal, pulse/direction signal wires and motor
wires should not be tied up together. It is better to separate them by at least 10 cm,
otherwise the disturbing signals generated by motor will easily disturb pulse
direction signals, causing motor position error, system instability and other failures.
If a power supply serves several Drivers, separately connecting the Drivers is
recommended instead of daisy-chaining.
It is prohibited to pull and plug connector P2 while the Driver is powered ON,
because there ishigh current flowing through motor coils (even when motor is at
standstill). Pulling or plugging connector P2 with power on will cause extremely high
back-EMF voltage surge, which may damage the Driver.
9. Protection Functions
To improve reliability, the Driver incorporates some built-in protection functions.
The MC856uses one RED LED to indicate what protection has been activated. The
periodic time of RED is 3s (seconds), and how many times the RED turns on
indicates what protection has been activated.Because only one protection can be
displayed by RED LED, so the Driver will decide what error to display according to
their priorities. See the following Protection Indications table for displaying
priorities.
Over-current Protection
Over-current protection will be activated when continuous current exceeds 16A or
in case of short circuit between motor coils or between motor coil and ground, and
RED LED will turn on once within each periodic time (3 s).
Over-voltage Protection
When power supply voltage exceeds 80±1 VDC , protection will be activated and
RED LED will turn on twice within each periodic time (3 s).
Has Error Protection
Motor power lines wrong & not connected will activate this protection. RED LED will
turn on four times within each periodic time (3 s).
Attention: When above protections are active, the motor shaft will be free or the
LED will turn red.Reset the Driver by repowering it to make it function properly after
removing above problems. Since there is no protection against power leads (﹢,﹣)
reversal, it is critical to make sure that power supply leads correctly connected to
Driver. Otherwise, the Driver will be damaged instantly.
10. Frequently Asked Questions
In the event that your Driver doesn’t operate properly, the first step is to identify
whether the problem is electrical or mechanical in nature. The next step is to isolate
the system component that is causing the problem. As part of this process you may
have to disconnect the individual components that make up your system and verify
that they operate independently. It is important to document each step in the
troubleshooting process. You may need this documentation to refer back to at a
later date, and these details will greatly assist our Technical Support staff in
determining the problem should you need assistance.
Many of the problems that affect motion control systems can be traced to electrical
noise, controller software errors, or mistake in wiring.

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Problem Symptoms and Possible Causes
Symptoms
Possible Problems
Motor is not rotating
Microstep resolution setting is wrong DIP switch current setting
is wrong Fault condition exists
Motor rotates in the wrong
direction
Motor phases may be connected in reverse
The Driver in fault
DIP switch current setting is wrongSomething wrong with motor
coil Control signal is too weak
Erratic motor motion
Control signal is too weak
Control signal is interfered
Wrong motor connection
Something wrong with motor coil
Current setting is too small, losing steps
Current setting is too small
Motor stalls during
acceleration
Motor is undersized for the application
Acceleration is set too high
Power supply voltage too low
Excessive motor and
Driver heating
Inadequate heat sinking / cooling
Automatic current reduction function not being utilized
Current is set too high