RHINO MOTION CONTROLS RMCS - 2303 User manual

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DC Servo Drive
10V - 30V DC, 50W with ASCII Modbus
RMCS – 2303
O erating Manual v1.0

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Contents
Introduction – Salient Features ......................................................................................................................... 3
Technical s ecifications and Pin descri tion ................................................................................................... 4
Drive and motor connections ............................................................................................................................ 4
Modes of o eration & Slave ID Addressing .................................................................................................... 6
Basics of servo drive ........................................................................................................................................... 8
How to use the drive .......................................................................................................................................... 9
Using PC Software ............................................................................................................................................. 10
Installation of Software ................................................................................................................................. 10
COM Port Selection ....................................................................................................................................... 12
Selection of Modbus Slave Address ............................................................................................................. 13
Para eters - Read, Write, Save & Reset .................................................................................................... 14
Control Modes................................................................................................................................................... 16
Analog Control Mode .................................................................................................................................... 16
Digital Speed Control Mode.......................................................................................................................... 18
Position Control Mode .................................................................................................................................. 20
Modbus Registers ............................................................................................................................................. 23
Brief Description of all Registers .................................................................................................................. 24
Control Through Microcontroller (Arduino) .................................................................................................. 27
Hardware Connection ................................................................................................................................... 27
Library Installation ......................................................................................................................................... 28
Description of all Functions .......................................................................................................................... 29

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Introduction – Salient Features
Rhino Motion Controls RMCS-2303 with UART ASCII is a high performance dc servo drive 10–30 V DC) designed
for optimized operation of any DC Servo motors with quad encoder feedback. This is an amazing cost effective
solution to provide closed loop servo control for various applications. The salient features of this drive:
• This drive provides a closed loop speed and position control for DC motor with encoder.
• The motor programmed speeds are maintained irrespective of the voltages supplied.
• Also by using this drive, the rated torque of the motor is available at all speeds and the torque does not
decrease with change in speeds.
• It is possible to run the motor in three different modes, Analog speed control mode, Digital speed control
mode and Position control mode.
• It has short-circuit protection for the motor outputs, over-voltage and under-voltage protection and will
survive accidental motor disconnects while powered-up.
• This drive is configured using MODBUS ASCII protocol via UART.
• There is a function in the drive for setting the Modbus Slave Address from 1 to 7 using physical jumpers
Hardware Setting) or using PC GUI or any other device like PLC or microcontroller which can provide
proper data output on ASCII Modbus.
• There are three user modes in the drive :
o Mode 0 - Analog Control Mode
o Mode 1 - Digital Speed Control Mode
o Mode 2 - Position Control Mode

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Technical specifications and Pin description
Supply Voltage and Current
Specification Min Max Units Comments
Supply Voltage 10 30 Volts DC Between +Ve and GND
Phase Current 0.5 3 Amps Peak 5 Amps per phase
Pin description of the drive is as per below image:
(Pins -7 are used for drive
Configuration and UART control)
Pin No.
Description
8 GND
9 +5VDC
10 ENC_B/Hall W
11 ENC_A/Hall U
12 Hall U
13 W
14 Motor- / V
15 Motor+ / U
16 VDD
17 GND
Pin No. Description
1 GND
2 RXD
3 TXD
4 ENABLE
5 ADC
6 DIRECTION
7 BRAKE
Pin No.
Description
JP
Jumper 1
JP2
Jumper 2
JP3
Jumper 3
(Pins 8
-
7 are connected to
motor and power supply as
described)
(JP to JP3 are used for
Hardware setting of slave ID)

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Drive & Motor Connection
Drive Pin outs
Pin No. Description
8 GND
9 +5VDC
10 ENC_B/Hall W
11 ENC_A/Hall U
12 Hall U
13 W
14 Motor- / V
15 Motor+ / U
16 VDD
17 GND
Motor Pin outs
Motor Wire Color
GND Black
VCC 5 V DC ) Brown
ENC_B Encoder B) Red
ENC_A Encoder A) Orange
M- Motor-) Yellow
M+ Motor+) Green
Power Supply Pin outs
VCC – 10 to 30V
GND

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Modes of Operation
The drive can be configured in the following three modes
1. Mode 0 Analog speed control mode :
a. In this mode the speed of the Rhino DC Servo motor can be controlled by an externally connected
Potentiometer.
b. Speed can be increased or decreased manually based on requirement using potentiometer.
c. The drive will provide full torque at all speeds within the range.
d. However the potentiometer has to be connected via a voltage divider to provide a maximum of 3.3
volts so as to not damage the drive.
e. Also the Enable, Brake and direction pins have to be connected as per configuration requirements.
2. Mode Digital Speed control mode with direction control :
a. In this mode the speed and direction of the DC servo motor is settable / controllable via a Computer
or any microcontroller board like Arduino or PLC or any other Modbus ASCII compatible device.
b. Like the analog mode here there is no compromise in the torque output of the motor irrespective of
the operational speed and voltage supply and control at higher speeds.
c. This mode can be used when multiple motors are to be used to run at exactly the same RPM and
same torque even though the voltage supply might be different.
d. Also in this mode the direction of the motor can be controlled digitally via Modbus ASCII commands
to run the dc servo motor in both directions
e. In applications like conveyor belts where speed control is critical and industrial robotic applications
like solar cleaning robots where straight line motion is critical for correction operation of the
equipment, the digital speed control mode can provide optimal results.
3. Mode 2 Position Control Mode :
a. In this mode Speed, Direction, Acceleration and Position of motor can be controlled.
b. The position control mode is suitable in applications where exact movement of motor is required.
This can be used in precision applications like machine control, motion control or robotics.
In all modes absolute encoder position and speed is available on Modbus.

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Slave ID Addressing
Multiple drives with different slave addresses can be used with a single controller on single UART bus. For this all
drives should have a unique Slave Address. Using the GUI software or Modbus commands, the slave ID can be set
from 1 to 247. However, slave ID from 1 to 7 can be set using physical jumpers also. As shown in the image below
there are three jumpers marked by a red circle shown in the image below.
The three jumpers JP1, JP2 and JP3 can be set in the configuration as per the below table to provide a physical
slave address to the drive. In the below table a value of ‘0’ corresponds to a state where the jumper is not connected
and a value of ‘1’ corresponds to a state where the jumper is connected. If none of the jumpers are connected the
drive has been programmed to use the Slave ID 11 in default mode which can be changed from 1 to 247 using GUI
software or Modbus commands.
Drive will check jumpers on startup. If no physical jumper is connected it will use programmed slave id.
Slave ID JP JP2 JP3 Image of connection on the Drive
1 0 0 1
2 0 1 0
3 0 1 1
4 1 0 0
5 1 0 1
6 1 1 0
7 1 1 1

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Basics of a servo drive
This is a servo drive to work with quad incremental encoder and dc motor. When the drive starts up the encoder
position is set as 0. With reference to the start position drive will always have a 32 bit number keeping track of
movement. It can be set to 0 at any point.
This servo drive works with quadrature encoder. The quadrature encoder also known as quad encoder or incremental
encoder gives two channels of pulses output. It can be of optical or magnetic type.
The basic concept is the encoder gives output of two channels of pulse streams say channel A and channel B to
drive, when A is leading B or B is leading A the drive can also determine the direction of movement.
So drive can calculate the speed and direction of motor according to the pulses if number of Lines per Rotation is
known. For each line drive gets 4 counts, for example if encoder is 334 lines drive can get 1336 334 x 4) counts per
rotation. This parameter can be set in register 10. It's a 16 bit unsigned number having range of 1 to 65535.
In any of the 3 modes drive manages speed, direction, acceleration, deceleration, position of motor and voltage and
current given to the motor based on set parameters, gains and feedback from encoder. This is a close loop system
means in position mode the drive always tries to make the error which is difference between the required position and
error to 0, in case of speed mode it tries to make the speed same as set speed.
The voltage and current given to motor is also managed by drive to provide higher torque when required. This also
means that even at lower speed, higher torque up to the maximum torque available in motor is possible.

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ow to use the drive:
The drive needs to be configured to run in any one of the three modes described in the above section to make a
closed loop control system. The drive can be configured using a PC with GUI software / Modbus controller / Arduino
Board.
To configure the drive for a closed loop system
• PC with GUI software for Rhino 2303 drive or any generic Modbus software Like Modbus Poll)
o GUI software
https://robokits.co.in/downloads/Rhino%20DC%20Servo%202303%20Config%20Setup.exe
o Modbus Poll demo version - https://www.modbustools.com/download.html
• RMCS-2303 UART ASCII Encoder DC Motor Driver
o https://robokits.co.in/motor-drives-drivers/encoder-dc-servo/rhino-industrial-encoder-dc-motor-
driver-50w-with-uart-ascii-compatible-10-to-30-v-10a
• Encoder DC Servo Motor Any DC motor 10-30VDC 50W max with encoder)
o https://robokits.co.in/rhino-planetary-encoder-dc-servo
o https://robokits.co.in/rhino-ig32-precision-dc-servo
o https://robokits.co.in/motors/encoder-dc-servo/high-torque-dc-encoder-motor
o https://robokits.co.in/motors/encoder-dc-servo/high-torque-high-precision-motor
• Industrial Power Supply below is a recommended supply. It can vary as per your requirements)
o https://robokits.co.in/power-supply/industrial-power-supply/24v-10a-industrial-power-supply
• USB UART Module
o RKI-1154 CP2102 - https://robokits.co.in/control-boards/interface-boards/cp2102-usb-uart-module
• External 10K Potentiometer and resistors for analog Speed Control mode only).

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Software Installation
Software is available here
https://robokits.co.in/downloads/Rhino%20DC%20Servo%202303%20Config%20Setup.exe
Download and run the setup executable.
• Click Next button
• Verify installation destination and click Next

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• Click Finish when Installation Successful message shows up.
Now, Software is ready to use. find the shortcut on desktop and open the software.
Once the Software is installed connect USB-UART as per shown in below figure.

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COM port Selection
Select COM Port for USB-UART , then click on "Connect" button.
You may look in 'Devices and Printers' or 'Device Manager' for specific serial port of your device. The software
supports serial ports up to COM 2 only. If your device's port number is higher you can change it in - Device Manager
> Ports (COM & LPT) > Double click on device name > Port Settings > Advanced > COM Port number
Once your drive is connected to COM Port and it shows "Connected" message.
When the drive communicates with software You can see a blinking Green indication.

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Selection Of Modbus Slave Address
There are two ways to select Modbus Slave address.
. If Slave address is already known, it can be directly selected from drop box.
2. If slave address is not known or multiple drives with multiple addresses are connected on serial bus, click search
button. This will search for all slave ids from 1 to 247. If any response is received from slave id it will give indication in
status bar and list the drive in 'Available Slaves' drop down box.
To search slave address click on "Search". Once all the connected devices are found click on "Stop Search". Select
any of detected slave address in Modbus Slave Address drop down box and drive will start communicating to
software.
Make sure no multiple drives with same slave address is connected on serial bus.
Once any drive is connected and slave id for the same is selected, software will read parameters of the drive. It can
also be done manually by clicking 'Read Parameters' button.

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Parameters
READ PARAMETERS
"Read Parameters" is used to read current parameters of drive.
SET A PARAMETER
• Pressing 'Enter' on text box will change the parameter in drive but it will not be saved permanently.
'Write Parameters' button must be clicked to save all parameters permanently.
• Set Position Proportional gain, Velocity Feed Forward gain and Position Integral Gain as per
requirement. These can be used to remove vibrations and making movement of motor accurate.
• Set Modbus slave address and lines per rotation. Lines Per Rotation is very important because it does
have effect on indication of speed feedback.
• If slave address is changed the software will automatically change the slave id of currently connected
device.
• Set Speed and Acceleration as per the requirement of application.
WRITE PARAMETERS
Once all the parameters are entered and tested, click on "Write Parameters" to save all parameters in drive.
These parameters will be changed permanently. Notification will be shown as below when all parameters
are written successfully.

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RESET PARAMETERS
To reset the drive to default configuration click 'Reset Parameters' button. This will set all parameters to
default values. When button is clicked software will ask for confirmation.
Click on "Yes" to reset the drive. After Clicking on 'Yes' if reset is successful confirmation message will be
shown. Power off and Power on the drive to load default parameters. If any physical jumpers are preset at
this point the slave id of the drive will be according to that otherwise slave id will be 11.

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Control Modes
Motor can be run in 3 different modes - 0 : Analog Mode, 1 : Digital Speed Mode, 2 : Position Mode
Mode 0 - Analog Control Mode
In this ode drive can be controlled using an external potentio eter or analog voltage input. As this is
a close loop drive, high torque (up to the axi u torque otor can provide) is available even at low
speed.
• Connect external potentiometer to change speed of motor as per diagram.
• Connect enable Pin 4) of drive to GND Pin 8) to enable motor in analog mode.
• Direction of motor can be changed in analog mode by connecting the Direction Pin 6) to the GND Pin 8).
• Electronic brake can be applied to motor by connecting Brake to GND - Pin 7) to GND Pin 1).
Hardware Connection:

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Drive to PC/Analog Connection
Set drive to Analog Control Of Motor in Software:
• By default the drive is in Analog mode. However if the mode is changed to some other then it can be set
through software.
• Connect drive to PC and select Analog Control Mode in Operation Mode
• After selecting analog control mode click on "Write Parameters" to always start the drive in analog mode.
CP2 02 Pin outs
GND
TXD
RXD
Drive Pin outs
Pin No. Description
1 GND
2 RXD
3 TXD
4 ENA
5 ADC
6 DIR
7 BRK
Potentiometer Pin outs
GND GND
Output Signal
VCC 3.3 V DC
Voltage Divider Pin outs
GND GND
3.3V Signal
5 V 5 V DC

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DIGITAL SPEED CONTROL MODE
• In this mode the drive works in speed mode. It tries to reach and maintain the speed as per set parameter.
• The speed can vary depending upon load and gains set.
• Make sure that the set speed is always less than the motor can actually reach, otherwise the drive can give
uncertain result. For example if the maximum speed motor can reach at given voltage is 18000 always set
speed less than 18000 RPM.
Hardware Connection:
Digital Control Mode in Software:
a). To run your motor on digital speed control mode select this mode from operation mode.

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b) In this mode speed of motor rpm) can be controlled by changing value from 0-65535.
1. Speed can be increased and decreased using "+" and "-" respectively.
2. Enable Motor : Once speed is set click on "Enable Motor" to run motor on set speed.
3. Change Direction: Change the direction of motor. Can be done when motor is running or stopped.
4.Speed Feedback: Current speed feedback from drive. This depends on actual speed measured by encoder and
Lines per rotation setting.

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POSITION CONTROL MODE
The position control mode allows to go to absolute position with reference to 0 as start position. Current position can
be set to 0 at any point of time. The drive also manages the speed and acceleration/deceleration as per set
parameter while responding to any change in set position.
When a 32bit value is set through register 16 and 18 the drive will try to move motor to that position. It can be
updated even when motor is moving. Motor can be stopped any time or speed can be changed anytime even while
moving.
Hardware Connection:
COUNT CALCULATION:
Lines per rotation concept is very important for Position Control mode. For example we will use
HIGH TORQUE HIGH PRECISION ENCODER DC GEARED MOTOR 12V 200RPM RMCS-5014)
https://robokits.co.in/motors/encoder-dc-servo/high-torque-high-precision-encoder-dc-geared-motor-12v-200rpm
Lines per rotation = 334
For one rotation of encoder, the no of counts = 334 x 4 = 1336 As it is quad encoder)
So for 1336 steps, the base motor would move one rotation.
POSITION
MODE