Anaheim Automation MDC100-050101USB User manual

#L011213 July 2018

#L011213 1 July 2018
Table of Contents
Section 1: Introduction ............................................................................................................2
Description .................................................................................................................................2
Methods of Communication ......................................................................................................2
Baud Rate ...................................................................................................................................3
Status LEDs ...............................................................................................................................3
Electrical Specifications .............................................................................................................3
Control Inputs/Outputs ...............................................................................................................4
Ordering Information .................................................................................................................4
Dimensions/Switch Locations ...................................................................................................5
Wiring Diagrams ........................................................................................................................5
Terminal Descriptions ................................................................................................................6
Section 2: Functions .................................................................................................................7
PI Tuning ...................................................................................................................................8
Section 3: BMC100 Windows Software .................................................................................9
Installation ..................................................................................................................................9
Getting Started ...........................................................................................................................9
BMC100 Settings and Functions .............................................................................................11
Section 4: Direct Talk Mode .................................................................................................12
COM Port Settings ...................................................................................................................12
Command Summary ................................................................................................................13
Troubleshooting .......................................................................................................................22
Error Codes ..............................................................................................................................22
Appendix 1: ASCII Table for Direct Mode .........................................................................25
Copyright .................................................................................................................................25
Disclaimer ................................................................................................................................25
Warranty ..................................................................................................................................26
Trademarks ..............................................................................................................................26

#L011213 2 July 2018
Section 1: Introduction
The MDC100-050101USB is a Microcontroller based Programmable Brushless DC
Motor Controller with Hall Sensor feedback for accurate speed measurement. It provides
flexible, independent control of a Brushless DC motor from computers, or any machine
controller with a USB. It is also capable of standalone operation, making it an embedded
machine controller. The easy-to-use Windows software, BMC100, can be used to directly control
motion of the motor for Real Time Movements through USB Communication or to set up the
parameters for stand-alone use.
The MDC100-050101USB has 34 commands, which are easy-to-remember for direct
control of a brushless motor. The MDC100-050101USB communicates via USB with PC or
PLCs. The MDC100-050101USB communicates via an USB data bus. A windows driver is
provided to communicate with the MDC100-050101USB through a virtual comport from the PC.
This driver will turn any USB port into a virtual comport, thus enabling simple commands to be
sent to the MDC100-050101USB . To use the BMC100 software, the virtual comport driver must
be installed. The MDC100-050101USB uses only 2 watts at 24 VDC with no motor running.
Description
The MDC100-050101USB provides accurate control of Motor speed, direction, coast and
brake for a Brushless DC Motor. MDC100-050101USB requires the user to set the number of
poles in the motor for accurate measurement. It is embedded with a Proportional-Integrator (PI)
controller program. Proportional and Integrator Constants, Kp and Ki, can be programmed using
the BMC100 Windows Software or in Direct Mode. The controller has two modes through
which it can control the speed of the motor: Analog Mode and Digital Mode. In Digital Mode,
the controller is very accurate in keeping the motor running at the desired speed. The Analog
Mode provides standalone functionality to the controller with a dynamic DC voltage input to
control the speed of the motor. An analog voltage input can be used to set the desired speed
between the upper and lower programmable limits.
Methods of Communication
There are two methods for sending commands to the MDC100-050101USB. One is to
directly talk to the MDC100-050101USB using Direct Talk Mode (Connected to the Controller
via a USB Type-B Connector). This is usually used with a computer or PLC (Programmable
Logic Controller), where the computer or PLC gives the MDC100-050101USB serial
commands. The second way to give commands to the MDC100-050101USB is to use the
software program BMC100 for manual control. The BMC100 software should be used when the
MDC100-050101USB is the main controller.

#L011213 3 July 2018
Baud Rate
A term used frequently in serial data communications, a “baud” is defined as the
reciprocal of the shortest pulse duration in a data word signal, including start, stop, and parity
bits. This is often taken to mean the same as “bits per second,” a term that expresses only the
number of “data” bits per second. Very often, the parity bit is included as an information or data
bit. The MDC100-050101USB accepts a baud rate of 38400 only.
Status LEDs
When powered and operated properly, the PWR/ERR LED will be green. When a
communication error occurs, the LED will change to RED, and an error code will be generated in
the error code register. To read and clear the error with the software, click on the “Read All”
button. To read and clear the error while in “Direct Mode,” use the error code “!” command.
Once the error has been read and cleared, the LED will return to green and the error code register
will be cleared to 0. Refer to the table on page 22 for a complete list of the error codes. The RX
LED will blink when data is being received from the PC. The TX LED will blink when data is
being transmitted back to the PC. The BUSY LED will turn on whenever the motor is running
and turn off when the motor is stopped. The FAULT LED turns on if the temperature of the
controller becomes too high or if too much power is applied or if the current limit is reached. The
FAULT LED also turns on when COAST function is applied. In case of current overload, break
will be automatically applied to the controller and the motor will not restart until the current limit
is met.
Electrical Specifications
Power Requirements:
20-50 VDC
Hall Sensor Power Outputs:
6.25V @ 30mA (Max)
Operating Temperature:
0 to 60 degrees C
Baud Rate:
38400 Baud, Fixed
Data Format:
Half-Duplex, 1 start bit, 8 data bits, no parity, 1 stop bit

#L011213 4 July 2018
Control Inputs/Outputs
Run/Stop: (TB1, Pin 1)
Logic “1” (open) - Motor will not run and if running will come to a stop rapidly.
Logic “0” = Motor will run.
Analog Input Voltage (TB1, Pin 2): 0 to 5VDC
BUSY Output: Open - Drain Type. Vce (max) = 40VDC, Ic (max) = 50mA
This output will conduct current when active, and be open when not active. Current needs to be
limited into this pin. For the MDC100-050101USB Series, this output is a complete output.
Ordering Information
The table below lists a variety of products available from Anaheim Automation, Inc.
These products include those covered by this manual, along with supporting cables and devices.
We are continually adding new products to our line, so please consult Anaheim Automation, Inc.
or its representatives for information on the latest releases.
Part Number
Description
MDC100-50101USB
Featured brushless motor controller with hall sensor feedback.
AAUSB-AR-6
USB Communication cable that matches MDC100-050101USB
PSAM 24V 2.7A
DC Power Supply 24V at 2.7 Amps (60 Watts)
PSAM 24V 5.2A
DC Power Supply 24V at 5.2 Amps (125 Watts)
PSAM 24V 8.3A
DC Power Supply 24V at 8.3 Amps (200 Watts)

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Dimensions/Inputs Locations
Note: All units are in inches.
Wiring Diagrams

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Terminal Descriptions
Terminal Block 1.
Position
Description - Outputs to Motor
1
Phase A
2
Phase B
3
Phase C
4
HALL Power (5VDC)
5
HALL A
6
HALL B
7
HALL C
8
HALL GND
Terminal Block 2.
Position
Description - Inputs
1
Run/Stop
2
Analog Input Voltage
3
Busy
4
GND
5
GND
6
DC Power Supply (20-50VDC)

#L011213 7 July 2018
Section 2: Functions
Run At Given Set Point: This command causes the motor to start spinning at the set point
speed. The set point value is in RPM. When the Set Point speed is too high for the motor or the
controller to reach or if the load is too much for the motor to handle, the motor will run at the
maximum speed possible. The motor will also run at the given set point with RUN/STOP input.
Note: If the motor is started Digitally, it has to be stopped digitally. And if it is started with the
RUN/STOP input, it has to be stopped through the RUN/STOP input.
Hard Brake: This command causes the motor to come to an immediate stop. If the motor is
moving fast, it will experience a jerk motion.
Coast: This command causes the motor to stop with a constant deceleration and therefore motor
will not experience a jerk-like motion.
Go Clockwise:This command changes the direction of the motor to clockwise.
Go Counter-clockwise:This command changes the direction of the motor to counterclockwise.
Analog Input: One can start the motor in Analog mode via the BMC100 software of Analog
Run/Stop Input. To set the speed Analog Voltage Input will read a voltage between 0 and
+5VDC and based on the ”upper and lower” limits of the function, a set point speed will be
calculated for the motor to go to between the two limits. For example, if the lower limit is set to
0 RPM and the upper limit is set to 5000 RPM, and the analog input is set at +2.0VDC, then the
motor will go to set point of 2000 RPM. Changing the lower limit to 1000 and the voltage to
+3.2VDC, the motor will go to set point of 3560 RPM.
See examples below for calculations of the analog inputs.
(Upper-Lower) * (Voltage/5) = X
Lower + X = Frequency
Speed(rpm) = Lower Limit + ((Upper Limit - Lower Limit) * (Analog Voltage/5))
Example1: If Analog Voltage = 2V
Speed = 0 + (5000 - 0) * (2 / 5) = 2000 RPM
Example2: If Analog Voltage = 3.2V
(5000 - 1000) * (3.2 / 5) = 2560
1000 + 2560 = 3560 RPM
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/Stop Input:Grounding this input will cause the motor to turn on in either Mode and
making it High will stop the motor using either Coast or Hard Brake depending on which
command was used last. If Coast was used last, it will Coast.
Set Address: This command sets the address of the Controller.

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Fetch Address: This command fetches the address of the Controller.
Read Error: This command reads the error. These errors are explained in the error codes section
on page number 22.
PI Tuning
The MDC100-050101USB implements an optimized PI controller to control the speed of a
brushless motor. The following chart will help you find the optimum settings for your system.
Parameter
Increase
Rise Time
Overshoot
Settling
Time(Ts)
Steady State
Error (Ess)
Ki (0-150)
↑
↓
↑
↓
Kp (0-254)
↑
↑
↑
No Effect
IV (0-1400)
↑
↑
↑
No Effect
Explanation:
Ki is the integrator constant for the closed loop PI controller. This is the most important constant
for bringing the running RPM close to the Set Point RPM.
Kp: If the difference between the running RPM and Set Point RPM is too great. the power
applied to the motor is increased or decreased by the gain value before the PI controller takes
over.
IV (Initial Value): Initial value is the initial power applied to the motor by the controller. If the
load requires higher torque, a higher initial value is required to start spinning the load. If the load
on the motor is very small and if the Initial Value is really high, the motor may experience a jerk
motion.

#L011213 9 July 2018
Section 3: BMC100 Software
The BMC100 software is a handy utility that supports Anaheim Automation's MDC100-
050101USB controller. The BMC100 uses a Serial Port and our proprietary Anaheim
Automation protocol. This protocol is described in detail in the "Direct Talk Mode" Section.
After connecting your PC to the MDC100-050101USB via a USB Cable, the BMC100 software
can easily perform the following tasks:
•Exercise and monitor the MDC100-050101USB Controller
•Directly communicate with the MDC100-050101USB Controller
Installation
Software
•The BMC100 software is available for download online on our website menu
under Download Software. The link to this web page is provided below:
http://www.anaheimautomation.com/downloads/software/software.php
•The BMC100 is compatible with all versions of Windows including Windows 8,
Windows 7, Windows Vista, and Windows XP.
Windows 8/7/XP/Vista Installation
1. http://www.anaheimautomation.com/downloads/software/software.php
2. Scroll down to BMC100 Program and Download the .zip file by clicking
on the download link. Choose a download destination folder and
download the file.
3. Extract the BMC100 folder.
4. Enter the folder and double click setup.exe file and follow the prompts to
install the software.
Getting Started
1. Connect MDC100-050101USB to PC via USB.
2. Apply power to the MDC100-050101USB
3. Double click on the BMC100 icon to run the BMC100 Software.
4. Select MDC100-050101USB from the drop down menu and Click Select.
5. The Software will attempt to establish communications with the controller; if a
connection is established, the BMC100 GUI will appear as seen in the picture on the
following page.

#L011213 10 July 2018
6. If the software did not automatically establish a connection with the controller, the user
can manually connect to it after making sure that the controller is powered on and
connected to the PC via USB. In order to do this, click on the Setup menu and then
Connect. The connect window will pop up as shown below. Select the appropriate COM
port from the dropdown menu and click on Connect Controller.
7. Once the connection is made, all the other buttons will be enabled. Also, the default (if
the controller is new) or previously programmed parameters will fill the given fields.

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Motion Control
Mode
Sets Analog or Digital Mode
Direction
Set Clockwise or Counter Clockwise Direction Looking at Motor Shaft
Freewheel
Let the Motor Coast to a Stop when a Stop Command is Received
Brake
Immediately Stop the Motor when a Stop Command is Received
Start Motor
Run The Motor at the Set Point Speed
Stop
Immediately stops or lets the motor coast to a stop depending on the brake setting
Motor Parameters
Set Poles
This Field Sets the Poles of the Motor
Set Digital Set Point
Sets the Set Point Running Speed in the Digital Mode
Set Analog Min. Limit
Sets the Lower Speed Limit for Analog Mode
Set Analog Max. Limit
Sets the Upper Speed Limit for Analog Mode
Read All
Update all the Parameters
Factory Reset
Set All the Parameters to the Factory Default
These functions are explained in more details in the Functions Section.
Controller Parameters
Set Kp
Sets the Proportional Constant
Set Ki
Sets the Integrator Constant
Set Gain
Sets the Gain Constant
Set IV
Sets the Initial Value Constant
Read Error
In Case of a Fault LED (Red) on the Board, Read Error
*Warning: Ignore the FAULT LED followed by a Coast Command as this is a built in
hardware feature that can not be replaced.
In order to fine-tune the controller for your application, look at the PI Tuning Section.
The Speed Parameters are constantly updated once the Motor is Started.
In order to disconnect the controller, just click on the "Disconnect Controller" button.
Warning: If the set point speed is too high for the motor to reach, the motor will run at the
maximum speed possible. Two possible reasons this could happen are:
1. Higher than possible torque required for the specific load.
2. Given set point speed is more than the limit of the specific motor.

#L011213 12 July 2018
Section 4: Direct Talk Mode
Direct mode is used to directly control motion for real time movements through serial
communication. The MDC100-050101USB controller has 34 commands, which are easy to
remember for direct control of a Brushless DC motor.
COM Port Settings
Baud Rate:38400
Data Bits:8
Parity:None
Stop Bits:1
Flow Control:Xon/Xoff
NOTE: The unit communicates in half duplex mode, therefore proper setup of hyper terminal is
necessary to view characters, if characters are to be echoed back to the screen.
Unit Selection:
In order to communicate with a unit, the @ command followed by the address of the unit must be
sent.
NOTE: There should be no spaces between the @ and address select. The factory default address
of the unit is 0.
How to select a unit:
@0 (Unit 0 is selected)
@1 (Unit 1 is selected)
@29 (Unit 29 is selected)
Instructions
All instructions require that no spaces be sent between the command and the parameter followed
by a carriage return. Carriage Return is ENTER on most Keyboards.
Example:
correct: @0(Command)(carriage return)
incorrect: @ 0 (Command) (carriage return)

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Command Summary
Note:
* dash (_) after @ symbol represents the address of the unit. The range for the address is 0-99.
All the commands are explained in detail at the end of the list. Other dashes(__) represent a
parameter.
**The dash in the specific command (@#__) represents any of the 34 commands above.
More detailed description of this command is in the command explanation below.
@_S
@_V*
@_,
@_VM
@_.
@_VS
@_+
@_VN
@_-
@_VX
@_A
@_VDS
@_D
@_VP
@_!
@_VD
@_P__
@_VMO
@_F
@_VST
@_M____
@_VKG
@_[____
@_VKP
@_]____
@_VKI
@_KI___
@_VIV
@_KG___
@%
@_IV___
@~__
@#__ **
D - Digital Mode.
Format: @0D(Carriage Return)
Description: Engage the Digital Mode.
Example: If the unit is stopped and it is in analog mode, @0D will put it in digital mode. This
command followed by @0S and then @0M2500 makes the motor run at 2500 RPM. If the unit is
running in Analog Mode, this command doesn't have any effect.
A - Analog Mode.
Format: @0A(Carriage Return)
Description: Engages the Analog Mode.
Example: If the unit is stopped and in digital mode, @0A will put it in analog mode. This
command followed by @0S or turning the Analog Brake Switch from OFF to ON makes the
motor run at the speed calculated based on Analog Input Voltage and the respective analog min.

#L011213 14 July 2018
RPM and analog max. RPM. The input will read a voltage between 0 and +5VDC, and based on
the “upper and lower” limits of the function, a max speed can be obtained based on a calculated
frequency between the two points. See examples below for calculations of the analog inputs.
Analog calculations.
(Upper-Lower) * (Voltage/5) = X
Lower + X = Frequency
Example 1: If voltage is 2V and if Upper and Lower Limits are 5000 and 0 respectively.
(5000 - 0) * (2 / 5) = 2000
0 + 2000 = 2000 RPM
Example 2: If voltage is 3.2V
(5000 - 1000) * (3.2 / 5) = 2560
1000 + 2560 = 3560 RPM
+ -Clockwise Direction
Format: @0+(Carriage Return)
Description: Makes the motor spin clockwise.
Example: When this command is sent to the controller, the direction of the motor becomes
clockwise whether the motor is running or not. If the motor is already running in clockwise
direction, there is no change. If it is running in counter clockwise when this command is entered,
the motor makes a quick stop and starts running clockwise at the set point speed it was already
running at.
-- Counter - Clockwise Direction
Format: @0-(Carriage Return)
Description: Makes the motor spin counter clockwise.
Example: When this command is sent to the controller, the direction of the motor sets to counter
clockwise whether the motor is running or not. If the motor is already running in counter
clockwise direction, there is no change. If it is running in clockwise when this command is
entered, the motor makes a quick stop and starts running counter clockwise at the set point speed
it was already running at.

#L011213 15 July 2018
S - Start Motor
Format: @0S(Carriage Return)
Description: Starts the motor in Analog as well as in Digital mode.
Example: When this command is sent, the motor starts running at the set point speed based on
other configurations. If the motor is started with @0S in analog mode, it can only be stopped
with @0, or @0. and not the input switch. In other words, if the motor is started digitally, it can
only be stopped digitally.
,- Coast
Format: @0, (Carriage Return)
Description: Coasts the motor to a stop if it is running in any mode.
Example: When this command is transmitted, if the motor is running, it comes to a stop without
any jerk motion. If the motor is not running, no effect is seen with this command. This
command also makes the Analog Input Brake a Coast. Therefore after this command is applied,
if the motor is restarted and is running in analog mode, and if the analog brake is applied, the
motor will coast to a stop.
.- Hard Brake
Format: @0. (Carriage Return)
Description: Engages Hard Brake if motor is running in any mode.
Example: When this command is transmitted, if the motor is running, the controller performs a
hard brake. When this brake is applied, the motor comes to an immediate stop. If the motor is
running at high RPM this may cause the motor to jerk and move a little. This command also
makes the Analog Input Brake a Hard brake. Therefore after this command is applied, if the
motor is restarted and is running in analog mode, and after that if the analog brake is applied,
the motor performs a hard brake as described.

#L011213 16 July 2018
M - Digital Set Point Speed
Format: @0M(RPM Value)(Carriage Return)
Description: Changes the set point speed of the digital mode to the speed represented by the
dashes. It has no effect in Analog Mode.
Example: @0M2600 will set the Digital Mode speed to 2600 revolutions per minute. If the
motor is running in digital mode at any speed, the motor will run at 2600 rpm after this command
is issued. If the motor is stopped but restarted in digital mode after this command, the set point
speed will run at 2600 RPM and the motor will go to 2600 RPM. Factory default is 2000 RPM.
[ - Analog Speed Minimum Limit
Format: @0[(RPM Value)(Carriage Return)
Description: Changes the lower boundary of the Analog Mode speed represented by the RPM
Value.
Example: @0[600 changes the lower boundary of Analog Mode speed to 600 RPM. @0[1900
changes the lower boundary of Analog Mode speed to 1900 RPM. One condition for this is that
the minimum speed has to be lower than or equal to the maximum speed. Therefore, if the
maximum speed is assigned to 1800 RPM, @0[1900 will yield an error. If this error happens, no
change is made to the minimum speed constant. This error is described in the Error Codes
section. This boundary is used in calculating the set point speed for analog mode based on the
formula described in the Calculating Analog Speed Section. Factory default is 1000 RPM.
] - Analog Speed Maximum Limit
Format: @0](RPM Value)(Carriage Return)
Description: Changes the upper boundary of the Analog Mode speed represented by the RPM
value.
Example: @0]2000 changes the upper boundary of the analog speed to 2000 RPM. @0]900
changes the upper boundary of analog mode speed to 900 RPM. One condition for this is that the
minimum speed has to be lower than or equal to the maximum speed. Therefore, if the minimum
speed is assigned to 2000 RPM, @0]1900 will yield an error. If this error happens, no change is
made to the maximum speed constant. This error is described in more details in the Error Codes
section. This boundary is used in calculating the set point speed for analog mode based on the
formula described in the Calculating Analog Speed Section. Factory default is 4000 RPM.

#L011213 17 July 2018
P - Set the Number of Poles
Format: @0P(Number of Poles of Motor)(Carriage Return)
Description: Checks and stores the number of poles as represented by the Number of Poles of
motor.
Example: This information is crucial for correct RPM calculations. The default number of poles
is 4. The options are 2,4,6,8,10,12. Therefore, @0P8 will set the poles parameter to 8. If the
current poles parameter is set to 6, @0P5 or @0P99 will throw an error as described in the Error
Codes section.
! - Error Code
Format: @0!(Carriage Return)
Description: Returns the error code as described in the Error Codes section.
Example: If the analog max speed is lower than the analog min speed, this command will return
128.
F - Factory Default
Format: @0F(Carriage Return)
Description: @0F restores all the parameters and variables to default. These values are described
in the Defaults on Start Up section.
KG - Set Proportional Value
Format: @0KG(Proportional Value)(Carriage Return)
Description: Checks and stores the initial Proportional constant as represented by the
Proportional Value.
Example: @0KG70 will make the Proportional constant 70. The range for KG is 0-254.
@0KG255 or @0KG1000 will return errors as described in the Error Codes Section. The default
value is optimized for a 4 pole Brushless motor with small loads on them. The higher the load,
the higher this value should be.

#L011213 18 July 2018
KP - Set Integrator Constant
Format: @0KP(Integrator Value)(Carriage Return)
Description: Checks and stores the Integrator constant as represented by the dashes.
Example: @0KP20 will make the Integrator constant 20. The range for KP is 0-150. @0KP151
or @0KP1000 will return errors as described in the Error Codes Section. The default value is
optimized for a 4 pole Brushless motor with small loads on them. The higher the load, the higher
this value should be.
IV - Initial Value Constant
Format: @0IV(Proportional Constant Value)(Carriage Return)
Description: Checks and stores the Initial Value constant as represented by the Proportional
Constant Value.
Example: @0KI2 will make the Integrator constant 2. The range for this is 0-1400 RPM.
@0IV1500 or @0IV10000 will return errors as described in the Error Codes Section. The default
value is optimized for a 4 pole Brushless motor with small loads on them. This value depends on
the inertia of the load. As the inertia increases, a higher initial force is required to get the load
spinning. For optimum results, this value should be increased as the load size or inertia is
increased.
VM - Return the Current RPM of the Motor.
Format: @0VM(Carriage Return)
Description: Returns the actual speed the motor is running at.
Example: If motor is running at 1925 RPM, @0VM command will respond with 'M1925'. If
motor is stopped, @0VM will respond with 'M0'.
VS - Return the Current Set Point RPM of the Motor.
Format: @0VS(Carriage Return)
Description: Returns the actual set point speed of the motor.
Example: It will return the calculated analog speed if it is in analog mode or the digital set speed
if it is in digital mode. If the set point speed is 1630 RPM, @0VS will return 'S1630'

#L011213 19 July 2018
VN - Return the Lower Boundary of the Analog Mode Speed.
Format: @0VN(Carriage Return)
Description: Returns the lower boundary of the analog mode speed.
Example: If the lower analog mode boundary is set to 1000 RPM, @0VN will return 'N1000'
VX - Return the Upper Boundary of the Analog Mode Speed.
Format: @0VX(Carriage Return)
Description: Returns the upper boundary of the analog mode speed.
Example: If the upper analog mode boundary is set to 3000 RPM, @0VN will return 'X3000'
VDS - Return the Set Point Speed of the Digital Mode.
Format: @0VDS(Carriage Return)
Description: Returns the Set Point Speed of the Digital Mode.
Example: If the digital mode speed is set to 2500 RPM. @0VDS will return 'DS2500'. It will do
this in analog mode too but in analog mode, this won't be the actual current set point of the point
of the motor. In analog mode, it will still return the digital mode speed.)
VP - Return the User Set Number of Poles For the Motor.
Format: @0VP(Carriage Return)
Description: Returns the user set number of poles for the motor.
Example: @0VP(Carriage Return). If the poles parameter is set to 6, @0VP will return 'P6'
VD - Return the Current Direction of the Motor.
Format: @0VD(Carriage Return)
Description: Returns the current direction of the motor.
Example: If the direction is set to counter clockwise, @0VD will return 'D-' or if the direction is
clockwise, it will return 'D+.' '+' for clockwise, '-' would be for counter clockwise.