MOTKA MK-200 User manual

M
MK K- -2 20 00 0
U
Us se er r’ ’s s M Ma an nu ua al l
Revision 1.1
MOTKA LLP

Table of Contents
1
1. .Introduction............................................................................................................5
2
2. .Getting Started.......................................................................................................8
2.1. Connecting the Power Supply..........................................................................10
2.2. Connecting the Host.........................................................................................10
2.3. Selecting Servo or Stepper...............................................................................11
2.4. Connecting Servo Motor..................................................................................12
2.5. Connecting Stepper Motor...............................................................................14
2.6. Connecting the Limits......................................................................................14
2.7. Connecting the Home Indicator.......................................................................15
2.8. Testing Our Connections .................................................................................17
2.9. Design Examples .............................................................................................18
3
3. .Package Information............................................................................................22
4
4. .Software Tools.....................................................................................................24
5
5. .Command Basics .................................................................................................25
6
6. .Revision History ..................................................................................................26

3
List of Figures
Figure 1 – Elements of motion control.....................................................................5
Figure 2 – The MK-200 2-Axis Motion Controller Surface Mount Module.........6
Figure 3 - MK-200 pin layout.....................................................................................8
Figure 4 – Power supply scheme...........................................................................10
Figure 5 – UART-to-UART interface with host.....................................................11
Figure 6 – UART-to-RS232 interface with host....................................................11
Figure 7 – Connecting to a brushless servo motor to Axis A.............................13
Figure 8 – Connecting to a brushed servo motor to Axis A................................13
Figure 9 – Connecting to a stepper motor to Axis A............................................14
Figure 10 – Connecting to forward and reverse limits to Axis A........................15
Figure 11 – Connecting to home indicator............................................................16
Figure 12 – Home operation....................................................................................16
Figure 13 - MK-200 package outline......................................................................22
Figure 14 - Recommended PCB footprint.............................................................23

4
List of Tables
Table 1 – MK-200 pin definitions..............................................................................9
Table 2 - Document revision history.......................................................................26

5
1
1. . Introduction
This User Manual targets application developers. It provides complete
information on how to use the MK-200.
For information on programming and the complete list of command
references, please refer to the Command Reference manual.
MK-200 is a 2-Axis Motion Controller Surface Mount Module that facilitates
implementation of motion control applications with simplicity, shortens
time-to-market, and achieves optimal cost-effectiveness. It is suitable for
scientific, industrial automation, robotic applications and hobby.
MK-200 is a fully functional motion controller requiring only an external
amplifier to complete a position control application. It is driven by a host
through an asynchronous serial port (UART). Figure 1 shows the elements
of motion control application using MK-200. Its servo compensation uses
32-bit position error, as well as PID control engine with acceleration and
velocity limits for position control. A set of essential and simple-to-use
instructions is provided to control the motion application and monitor
ongoing performance.
Figure 1 – Elements of motion control
Processor MK-200 Driver
Power
Supply
Motor
Encoder
UART
PWM/Dir
CHA/CHB

6
Features
Supports up to 2 axes
Configurable to support step or servo motors
5V tolerant PWM/Pulse and Direction outputs per axis to ensure
compatible with commercially-of-the-shelf amplifiers
Two channels (CHA and CHB) incremental encoder quadrature
input per axis
Two directional (Forward and Reverse) limits per axis
One home indicator per axis
One UART interface port, configured at 115200 bps, to interface
with a host processor
Easy-to-use ASCII-based programming instructions
Small footprint (35 x 28.5 mm) with castellated terminals for ease of
integration onto PCB
Spacing between castellated terminals is 2.54 mm, which is
compatible to common prototyping and bread boards
+5 V operation
Figure 2 – The MK-200 2-Axis Motion Controller Surface Mount Module

7
Related documents
•Command Reference.
•MOTKA Motion Companion User’s Manual.

8
2
2. . Getting Started
The pins layout and definitions of MK-200 are shown in Figure 3 and Table
1 respectively.
To get started, we can either solder the MK-200 directly onto a prototyping
board or place the MK-200 onto a prototyping breadboard using header
pins and make sure the contact between the pins and the MK-200 are
reliable. The instructions illustrated from Section 2.1 through Section 2.8
represent a typical application.
Figure 3 - MK-200 pin layout
1
2
3
4
+5V
Gnd
Gnd
+5V
A
-
CHA
A
-
CHB
A
-
HM
A
-
FL
A
-
RL
A
-
DIR
A
-
PWM
STEPPER A
STEPPER B
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Tx
Rx
B
-
CHA
B
-
CHB
B
-
HM
B
-
FL
B
-
RL
B
-
DIR
B
-
PWM
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15

9
Pins Pin Name Type
1
I/O Level
23
Function
1 +5V P - +5V supply
2 A-CHA I FT Axis A encoder input CHA
3 A-CHB I FT Axis A encoder input CHB
4 A-HM I FT,AL Axis A home indicator input
5 A-FL I FT,AL Axis A forward limit input
6 A-RL I FT,AL Axis A reverse limit input
7 A-DIR O FT Axis A direction output
8 A-PWM O FT Axis A PWM output
9 STEPPER A I FT,AL Axis A Stepper select
10 STEPPER B I FT,AL Axis A Stepper select
11 Reserved - - Reserved. Do not use.
12 Reserved - - Reserved. Do not use.
13 Reserved - - Reserved. Do not use.
14 Gnd P - Ground
15 Gnd P - Ground
16 Reserved - - Reserved. Do not use.
17 Reserved - - Reserved. Do not use.
18 Reserved - - Reserved. Do not use.
19 Rx - - UART Receive
20 Tx - - UART Transmit
21 B-PWM O FT Axis B PWM output
22 B-DIR O FT Axis B direction output
23 B-RL I FT,AL Axis B reverse limit input
24 B-FL I FT,AL Axis B forward limit input
25 B-HM I FT,AL Axis B home indicator input
26 B-CHB I FT Axis B encoder input CHB
27 B-CHA I FT Axis B encoder input CHA
28 +5V P - +5V supply
Table 1 – MK-200 pin definitions
1
P = Power, I = Input, O = Output
2
FT = Five voltage Tolerant
3
AL = Active Low

10
2.1.Connecting the Power Supply
The MK-200 requires a +5 V operating voltage. An embedded regulator is
used to supply the internal +3.3 V digital power. The +5 V pins must be
connected to a +5 V power supply with external decoupling capacitors
(one 100 nF ceramic capacitor for each +5 V) as shown Figure 4. The
decoupling capacitors shall be placed close to the +5V pins whenever
possible for best performance.
Figure 4 – Power supply scheme
2.2.Connecting the Host
A host is required to drive the MK-200 through the UART interface with the
following configurations:
Baud rate: 115200 bps
Data bit: 8
Stop bit: 1
Parity bit: None
Flow control: None
These configurations are not changeable.
The UART interface can be connected directly to another host processor
with a UART port (See Figure 5). If the MK-200 is to be connected to a
MK-200
+5V
Gnd
Gnd
+5V
100 nF
100 nF

11
host with RS-232C interface, a bus line transceiver such as MAX3232E
from Texas Instruments must be used (See Figure 6).
Figure 5 – UART-to-UART interface with host
Figure 6 – UART-to-RS232 interface with host
2.3.Selecting Servo or Stepper
The MK-200 supports 2 axes, namely Axis A and Axis B. Each axis can be
configured to operate with either a servo or stepper motor, depending on
the Stepper Select input (Stepper A and Stepper B).
Both axes of MK-200 are, by default, configured to operate with servo
motors. If stepper motors are used in an application, simply pull the
respective Stepper Select input (Stepper A and Stepper B) of the axis to
ground. It is important to note that the MK-200 reads these inputs only
once upon power up. Any change of configuration to these inputs
Host
Processor MK-200
Tx
Gnd
Rx
Tx
Rx
Gnd
MAX232
Rout
Din
Gnd
Rin
Dout
Gnd
Host Processor MK-200
Tx
Gnd
Rx
Tx
Rx
Gnd

12
(such as using jumpers in an application) will not be registered until
the next power up.
All Stepper Select inputs are pulled high internally. Hence, it is safe to
leave the inputs unconnected if servo motors are used (see Figure 7).
2.4.Connecting Servo Motor
MK-200 supports standard dc servo motor amplifiers operate with PWM
and Direction mode. It also supports standard 2-channel encoders with
CHA and CHB outputs. All PWM and Direction outputs, as well as CHA
and CHB inputs are 5 V tolerant. If amplifiers and encoders used in an
application utilise other operating voltage other than +5 V, level-shifter
must be used to match these voltages.
Figure 7 and Figure 8 show the typical connections of a brushless and
brushed servo motor to the MK-200’s Axis A respectively. Note that the
Stepper Select, Stepper A, in both cases are left unconnected.

13
Figure 7 – Connecting to a brushless servo motor to Axis A
Figure 8 – Connecting to a brushed servo motor to Axis A
Motor A
Motor B
HALL 1
HALL 2
HALL 3
Motor C
MK-200
Stepper A
Encoder
Brushless
Motor
CHA
A
-
Dir
A
-
PWM
A
-
CHA
Amplifier
B
A
Dir
PWM
A
-
CHB
Gnd
CHB
Gnd
(unconnected)
(must have common ground)
C
HALL 2
HALL 1
HALL 3
MK-200
Stepper A
Encoder
Brushed
Motor
Motor+
CHA
A
-
Dir
A
-
PWM
A
-
CHA
Amplifier
M
-
M+
Dir
PWM
A
-
CHB
Gnd
Motor
-
CHB
Gnd
(unconnected)
(must have common ground)

14
2.5.Connecting Stepper Motor
MK-200 supports standard stepper motor amplifiers operate with PWM
and Direction mode. When stepper operation is selected, MK-200 does
not support encoder inputs (CHA and CHB).
Figure 9 shows the typical connection of stepper motor to the MK-200.
Note that the Stepper Select, Stepper A, is connected to ground.
Figure 9 – Connecting to a stepper motor to Axis A
2.6.Connecting the Limits
There are two directional limits per axis, which can be used to prevent
collision due to over travelling. Leave these limits unconnected (inactive) if
we do not wish to use them.
Both Forward and Reverse limits are active low.
If the Forward Limit (FL) is active, it inhibits the forward motion
immediately. If the Reverse Limit (RL) is active, it inhibits the reverse
motion immediately. After a limit has been activated, further motion in the
direction of the limit will not be possible until the state of the limit returns
back to inactive state. This usually involves physically moving the
MK-200
Stepper A
Stepper
Motor
A+
A
-
Dir
A
-
PWM
Amplifier
A
-
A+
Dir
PWM
A
-
B+
B
-
B+
B
-

15
mechanisms or moving the motor in the opposite direction via instruction
set.
Figure 10 depicts the connection of standard slot sensors to these limits.
Figure 10 – Connecting to forward and reverse limits to Axis A
2.7.Connecting the Home Indicator
The MK-200 comes with one Home indicator (HM) per axis. Home
indicators are designed to provide mechanical reference points for a
motion control application. A transition in the state of the home indicator
alerts the controller that a reference point is reached by a moving part in a
motion control system.
These inputs are active low and can be used with external sensors, such
as slot sensor, as depicted in Figure 11.
MK-200
A
-
FL
Gnd
+5V
10K
10K
A
-
RL
10K
+5V
10K

16
Home operation is initiated by the Move Home (MH) instruction. MH
instruction accepts both direction and speed of search. Refer to Command
Reference for more information.
Move Home instruction initiates the corresponding PWM pulses and
Direction bit. In the example shown Figure 12, the MH instruction searches
in the forward (DIR is logic ‘0’) direction. Once the HM input is active (logic
‘0’), it toggles the Direction bit and reduces the speed of search, and
hence reverses the motion at a lower speed. This motion continues until
the HM input is inactive and the home operation is complete.
Figure 11 – Connecting to home indicator
Figure 12 – Home operation
MK-200
A
-
HM
Gnd
+5V
10K
10K
PWM
DIR
HM
Home sensor
active
Forward home search Home operation completes

17
2.8.Testing Our Connections
Having connected all the necessary circuitry described in the above
sections, we can start testing our application by sending a couple of
instructions. To do that, we can use the MOTKA Motion Companion
software or any third party software that can send and receive ASCII
characters such as Microsoft HyperTerminal.
In the example below, we assume a servo motor is connected to Axis A.
For more information to tailor your instructions to suit your tests, please
refer to the Command Reference for complete set of instructions and
explanations.
The first instruction is to check for Motor Type (MT). The response of ‘1’
indicates that MK-200 has configured Axis A to operate in servo mode.
Before we can move the motor, it must be enabled by sending the Servo
Enable (SE) instruction to Axis A. We get the first position (GP) and MK-
200 responses with zero. We then move the motor by 10,000 counts
relative to current position. Depending on the tuning of PID parameters
(KP, KI and KD) with respect to the loads, the response of the final
position obtained by GP may be different from the example below.
MT ?
1
SE T
GP ?
0
MR 10000
GP ?
10003

18
2.9.Design Examples
Here are a few simple C/C++ examples for using your controller. You may
use other languages to send the ASCII commands via the serial port.
Example 1 – Tuning of Controller
This example assigns the PID parameters to Axis A and read back for
confirmation.
CSerial port;
If(port.open(2, 115200)) // Open serial port and configured
{ // to baud 115200 bps
char Kp[7] = “KP 100”; // Set Proportional gain for Axis A
Kp[6] = 0x0D; // Terminate it with a Carriage Return
char Ki[7] = “KI 800”; // Set Integral gain for Axis A
Ki[6] = 0x0D; // Terminate it with a Carriage Return
char Kd[5] = “KD 2”; // Set Differential gain for Axis A
Kd[4] = 0x0D; // Terminate it with a Carriage Return
char query[5] = “KP ?”; // Query for KP
query[4] = 0x0D; // Terminate it with a Carriage Return
char readBuf[10]; // Container for reply
port.send(Kp, sizeof(Kp)); // Send KP to controller
port.send(Ki, sizeof(Ki)); // Send KI to controller
port.send(Kd, sizeof(Kd)); // Send KD to controller
port.send(query, sizeof(query)); // Query for KP
port.read(readBuf, sizeof(readBuf)); // KP is stored in readBuf
}
Example 2 – Profiled Move
In this example, Axis B moves a distance of 50,000 counts at the speed of
30,000 counts/sec and an acceleration and deceleration of 100,000
counts/sec
2
. It motor stops once it reaches 50,000 counts.

19
CSerial port;
If(port.open(2, 115200)) // Open serial port and configured
{ // to baud 115200 bps
char SE[6] = “SE, T”; // Servo enable for Axis B
SL[5] = 0x0D; // Terminate with Carriage Return
char SL[10] = “SL, 30000”; // Speed limit
SL[9] = 0x0D; // Terminate with Carriage Return
char AL[11] = “AL, 100000”; // Acceleration limit
AL[10] = 0x0D; // Terminate with Carriage Return
char DL[11] = “DL, 100000”; // Deceleration limit
DL[10] = 0x0D; // Terminate with Carriage Return
char MR[10] = “MR, 50000”; // Move Relative
MR[9] = 0x0D; // Terminate with Carriage Return
port.send(SL, sizeof(SL)); // Set speed limit
port.send(AL, sizeof(AL)); // Set acceleration limit
port.send(DL, sizeof(DL)); // Set deceleration limit
port.send(SE, sizeof(SE)); // Enable motor
port.send(MR, sizeof(MR)); // Move motor
}
Example 3 – Profiled Move of Multiple Axes
In this example, both Axis A and B move independently at the same time.
CSerial port;
If(port.open(2, 115200)) // Open serial port and configured
{ // to baud 115200 bps
char SE[8] = “SE T, T”; // Servo enable for Axis A and B
SL[7] = 0x0D; // Terminate with Carriage Return
char SL[15] = “SL 30000, 5000”; // Speed limits
SL[14] = 0x0D; // Terminate with Carriage Return
char AL[17] = “AL 100000, 80000”; // Acceleration limits
AL[16] = 0x0D; // Terminate with Carriage Return
char DL[17] = “DL 100000, 10000”; // Deceleration limits
DL[16] = 0x0D; // Terminate with Carriage Return
char MR[16] = “MR 50000, 75000”; // Move Relative

20
MR[15] = 0x0D; // Terminate with Carriage Return
port.send(SL, sizeof(SL)); // Set speed limits
port.send(AL, sizeof(AL)); // Set acceleration limits
port.send(DL, sizeof(DL)); // Set deceleration limits
port.send(SE, sizeof(SE)); // Enable motors
port.send(MR, sizeof(MR)); // Move motors
}
Example 4 – Reading of Position
The position of any axis can be queried with the GP instruction.
CSerial port;
If(port.open(2, 115200)) // Open serial port and configured
{ // to baud 115200 bps
char query[7] = “GP ?,?”; // Get position – A and B axes
query[6] = 0x0D; // Terminate with Carriage Return
char readBuf[10]; // Container for reply
char posA[5]; // Buffer for Axis A position
char posB[5]; // Buffer for Axis B position
int i = 0;
port.send(query, sizeof(query)); // Query for position
// Once controller received the command, it will reply the positions.
port.read(readBuf, sizeof(readBuf)); // Read the positions
// Positions replied contained in readBuf are separated by 0x0D
// Read position of Axis A
while(readBuf[i] != 0x0D)
{
posA[i] = readBuf[i];
i++;
}
// Read position of Axis B
while(readBuf[i] != 0x0D)
{
posB[i] = readBuf[i];
i++;