SCPC-2 Manual & Smart Control Servo (SCSxx) and TTLinker

The SCSxx smart control servo use special half-duplex UART bus as input source.
User need to use a SCPC-2 to connect the smart control servos to PC via USB port, or make a circuit to communicate to other host MCU (please refer to Schematic of the half-duplex UART).
If use Arduino to control SCServo, it needs to have a TTLinker connect to between Arduino and SCServo.
TTLinker is a signal conversion board. Arduino needs to convert its UART signals to the half duplex type and through TTLinker connect to SCServo. Also TTLinker have more interface used to kinds of sensor and compatible with Arduino.

This Quick start document will guide you to:

• Connect a smart control servo to your PC via USB port using SCPC-2
• Programmed SCServo’s parameters
• Run SCSxx servos though SCServo_Debug software
• Use Arduino to control SCSxx servos

For more details, such as instruction sets, electrical schematics and control table, please refer to SCSXX User Manual.

1 SCPC-2

Serial Control Programming Card for SCServo, Can be used as three functions:

• Test SCSxx robot servo.
• Programmed SCServo’s parameters.
• Upgrade SCServo’s firmware.

1.1 Schematic of the half-duplex UART

The SCPC-2 internal input interface circuit, a half-duplex UART. It’s compatible to Robotis’ Dynamixel AX-12A.
The following figure shows the schematic of the interface circuit.

1.2 System requirement and driver

The SCPC-2 contains a USB to RS-232 converter IC. User need a PC running Windows XP or Windows 7 (64), and need to install a driver to use this device.

1.3 Use the SCPC-2
1.3.1 Install driver

a. Download the driver from feetechrc.com, unzip it to a folder. (Click here for download)
b. Put SCPC-2’s USB cable into PC USB port. The SCPC-2’s red LED will bright, and the PC will be a dialog box informing you to install the driver. Following the wizard and choose the driver installation folder and click “Next” button.

c. When installations succeed, there will be a virtual serial port (USB serial port) in “Device manager” of the windows control panel, shown as the following figure. Please remember the COM number (I.E. COM1 COMx).

1.3.2 The pin-configuration of SCPC-2

1.3.3 Connection between SCServo and PC

Connect the SCPC-2’s servo cable to the “5264 servo port” on the SCServo, connect the 6~9V battery to the SCPC-2’s power cable.
Then use the SCServo_Debug software to setup and tune the smart control servos.

2 SCSERVO_DEBUG SOFTWARE

SCServo_Debug is software provide by FEETECH, it can be used to setup the SCServo and tuning its parameters. (Click here for download)

2.1 Check the connection and open software

Before open the software, make sure you:

• Connect the SCPC-2 to PC USB port, the power LED on (Running windows).
• Connect at least one SCSxx servo to the SCPC-2
• Connect the 6~9V battery power supplied
• SCServo driver installed

2.2 Set servo ID of SCSxx

Each SCSxx servo should have an ID for identification during communication. The default
ID is “1” of all new SCSxx servos. When use multiple SCSxx servos in one serial connection, you should assign different ID for each servo, otherwise all servos can’t work properly.
The following is an example to show you how to change the ID of a servo from ID ”1” to
ID ”2”.
Open SCServo_Debug.exe.
Click “Enter”, it will open the software if correct connection between SCPC-2 with PC. If not can’t open, and please double check SCPC-2 connection and driver installed..

Correct connection after click “Enter” the following window will appear:

The default baud rate of SCSxx servo is 1Mbps (1,000,000). User can change baud rate in “PROGRAM” tag’s window.

• Single Node: This check box should be checked when only one servo connected.
• Single Baud: The software will search the serial bus with the chosen baud rate.

STEP 1:
Select proper COM port (Virtual serial port number can be found in “Control panel/Device
Manager” of your Windows system, when SCPC-2 connected and driver installed),
STEP 2:
Select proper baud rate of SCSxx servo (The new servo default baud rate is 1Mbps).
STEP 3:
Click “Open” button, the software will connect the serial port. Then button will show “Close”. If not please check SCPC-2 connection and driver installed.
STEP 4:
Click “Search” button, you can see the following window. If the only servo found, you can click “Stop” button to stop search.

STEP 5:
Click the “PROGRAM” tag, and then click the only servo found in the list box (left side of the window).

STEP 6:
Click “READ” button to read all data from servo to show on software windows.
Input”2”in “ID” text

STEP 7:
The check box “Unlock” should be selected if you don’t want loses data after power off.
Then click “WRITE” button to download all data to servo. The changing ID operate is succeed and will take effect. The new ID will be stored in the servo, until you change it again.

Now click “Search” button again, you can see the servo ID is changed from 1 to 2.

2.3 Set servo other properties of SCSxx
2.3.1 Baud Rate

You can set baud rate of the SCSxx servos in the “PROGRAM” tag “Primary Set” window.
Operating steps the same as set ID.

Note: After set servo baud rate, you need to build a new baud rate connection. Otherwise, the servo can not to communicate with the software.

2.3.2 Servo Set and Dead Band

These two windows are to set to control PWM algorithm. It is not necessary need to reset.

2.3.3 Limitation

• Temperature Limitation is limit servo operation max temperature, over this limitation temperature servo will unload if has selected “Over Heat” protection.
• Torque Limitation used to limit the maximum output torque of SCSxx servos.

For example, If a “512” is assigned as torque limit, the output torque will be limited to half maximum torque. This function is very useful in many conditions. Over this limitation torque servo will unload if has selected “Over Load” protection.
Current limitation is not be used on SCSxx servos.
Punch is the servo’s minimum start-up torque. Please don’t set it too high. Otherwise, servo will work at un-stable.

• Voltage Limitation is used to set the voltage limitation. The physical voltage limit of SCSxx is 5 to 9V.
• Position Limitation

At Servo Mode
SCSxx can run from 0 degree to 210 degree, the parameter is 0 to 1023. In some case if you want to limit the servo position range from 10 degree to 190 degree, you can set position limit from 20 to 920(920 corresponding to 190 degree). In this case, when user give the servo a position command larger than 920, the servo will ignore and the position will be 920.
At Wheel Mode
If you want let SCSxx work at wheel mode, please set two parameters are both 0. Its mean that servo to rotate no limit.

• LED Error Flag this function are not be used in SCSxx servos.
• Unload Flag these check boxes are to set servo into protect status when work at over limitation.

3 TRY TO RUN SCSxx SERVOS

Click “ROBOT” tag to show the operate window.

In “Servo Operation” window, first “ID” text box is the ID of current active servo. All operation will be applied on this ID.
“Torque Out” check box is to enable the servo.
It must be selected before used software sending communications instructions to control servo.
“Wheel Mode” check box is to enable the wheel mode to work.
It need to programmed the position limitation are both 0.
“Write” check box is a command that it can communicate with current active servo, and control the servo move to “Goal” position with “Speed”.
“Sync Write” check box is a command that it can communicate with multiple servos at same time, and control multiple servos move to “Goal” position with “Speed”.
“Reg Write” check box is a command that it can communicate with multiple servos at same time, and control multiple servos move to “Goal” position with “Speed” after click “Action” button.
“Drawing Set” window, It must click “Draw” button if you want to see working status of servo.

“Status Monitor” window, you can see working status of the current active servo, also the status curve will show in the window if corresponding check box have be selected.

4 USE ARDUINO TO CONTROL SCSxx SERVOS

SCServo needs to have a TTLinker connect to between Arduino and SCServo.
If not please reference Connection to UART.
TTLinker is a signal conversion board. Arduino needs to convert its UART signals to the half duplex type and through TTLinker connect to SCServo. Also TTLinker have more interface used to kinds of sensor and compatible with Arduino.

4.1 Arduino library SCServo

We have SCServo library to be used when you are using Arduino to control SCServo. (Click here for download)
For example Arduino code as shown below.

#include
SCServo SERVO;
void setup()
{
Serial.begin(1000000);//init Serial baudrate
delay(500);
SERVO.EnableTorque(0xfe,1);
}

void loop()
{
u16 i;
for(i = 0;i < 1024; i++)
{
SERVO.WritePos(0xfe,i,100);//All Servo(broadcast) rotate to the position:i
delay(10);
}
for(i = 1024; i > 0; i—)
{
SERVO.WritePos(0xfe,i,100);//All Servo(broadcast) rotate to the position:i
delay(10);
}
}

This is show that using broadcast instruction to control all of SCServo on the BUS.
About instruction of WritePos, RegWritePos, ReadPos, RegWrite, Action, SyncWritePos and more introduce instruction please reference its instructions on website of feetechrc.com.

4.2 Connection to UART

To control the SCServo actuators, the main controller needs to convert its UART signals to the half duplex type. The recommended circuit diagram for this is shown below.

5 SUPPORTS

• For Technical support please visit our technical BBS:
• For other documents and software please visit our product web page:

6 IMPORTANT NOTICES

6.1. “Robotis”, “Dynamixel”, and “AX-12” are trademarks of Robotis Inc.
6.2. FEETECH reserves the right to make changes to its products or to discontinue any product

or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current and complete.

6.3. FEETECH warrants performance of its products

and related software to the specifications applicable at the time of sale in accordance with FEETECH standard warranty. Testing and other quality control techniques are utilized to the extent FEETECH deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements.

7 LIFE SUPPORT POLICIES

FEETECH PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS.
As used herein:
a. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user.
b. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.