ROBOTOUS RFT Series User manual

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1
6 Axis Force Torque Sensor
RFT Series
Installation and Operation Manual
REVISION 1.8
ROBOTOUS Co., Ltd.

RFTSeries|6AxisForceTorqueSensor

©ROBOTOUSCo.,Ltd.www.robotous.com|[email protected]
2
Contents
1. Caution ·························································································································································· 4
1.1. Notices ···································································································································································································4
1.2. Warning ·································································································································································································4
2. Installation ···················································································································································· 5
2.1. Overview ·······························································································································································································5
2.2. Power Supply Specifications ·························································································································································6
2.3. Wiring ····································································································································································································6
3. Operation ······················································································································································ 8
3.1. F/T Sensor Output Interfaces ·······················································································································································8
3.2. Communication Packets ·································································································································································8
3.3. Basic Operation ··················································································································································································8
3.4. Default Setting of Communication ············································································································································9
3.5. Packet Structure ·············································································································································································· 10
3.5.1. Packet Structure of CAN Interface ······················································································································································· 10
3.5.2. Packet Structure of UART interface······················································································································································ 10
3.6. Packet Definition ············································································································································································ 11
3.6.1. Summary of command packets ···························································································································································· 11
3.6.2. Read Model Name ······················································································································································································ 11
3.6.3. Read Serial Number ··················································································································································································· 12
3.6.4. Read Firmware Version ············································································································································································· 12
3.6.5. Set Communication ID (for CAN only) ·············································································································································· 12
3.6.6. Read Communication ID (for CAN only) ··········································································································································· 13
3.6.7. Set Baud-rate (for UART only) ······························································································································································· 13
3.6.8. Read Baud-rate ····························································································································································································· 1 4
3.6.9. Set Filter ·········································································································································································································· 14
3.6.10. Read Filter Setting ···················································································································································································· 15
3.6.11. Read F/T Data (once) ·············································································································································································· 15
3.6.12. Start F/T Data Output ············································································································································································· 17
3.6.13. Stop F/T Data Output ············································································································································································· 17
3.6.14. Set Data Output Rate ············································································································································································· 17
3.6.15. Read Data Output Rate ·········································································································································································· 18
3.6.16. Allowable Data Output Rate ································································································································································ 18
3.6.17. Set Bias ·········································································································································································································· 19

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3.6.18. Read Count of Overload Occurrence ··············································································································································· 19
3.6.19. Error Codes ·································································································································································································· 19
3.7. C Sample Code for Force & Torque Conversion ·············································································································· 20
3.7.1. CAN Interface ································································································································································································ 20
3.7.2. UART Interface ······························································································································································································ 21
4. Product Specification ······························································································································· 22
4.1. Performance specifications ························································································································································ 22
4.2. Data output interface ··································································································································································· 22
5. Product Ordering Information ··············································································································· 23
6. Contact Information (Technical Support) ···························································································· 24
7. APPENDIX: Dimensions of RFT Series ·································································································· 24

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1. Caution
1.1. Notices
The user must read and understand all of the instructions in this manual before using the RFT series F/T
sensors.
This manual covers installation, operation, specification, and ordering information of RFT series F/T
sensors..
1.2. Warning
Do not install and operate a F/T sensor that is damaged or lacking some parts.
Do not disassemble or repair the sensor for any purpose. This may cause irreparable damage to the
sensor and void the warranty.
Always take payload applied to the F/T sensor into consideration for safe usage.
Do not exert excessive forces or torques on the sensor. This can create incorrect measurement and
cause damage to the sensor. When force is applied to the sensor, torque is exerted on the sensor
simultaneously. Make sure all components of force and torque stay within allowed ranges. Even if a
component of them exceeds its limit, this may result in incorrect measurement of the other component.
Refer to Section 4.1 Performance Specifications.
If the sensor experiences a sudden change in temperature and humidity, the sensor’s temperature
correction feature may no longer function correctly and cause erratic sensor output. Please ensure the
sensor is not subject to sudden changes in temperature and humidity.
Do not remove or damage the label on sensor to maintain warranty.

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
©ROBOTOUSCo.,Ltd.www.robotous.com|[email protected]
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2. Installation
2.1. Overview
CapacitiveType
Sensingcapacitancevariationby
structuraldeformation
HighDurability
Mechanicaloverloadprotection,
noadhesive
LowCost
Simplestructure,simplified
fabricationprocess


ReliablePerformance
Immunitytoelectricalnoise,
robustcalibration,nosensordrift
EasyInstallationAll‐in‐onedevice
withembeddedsignalprocessing,
interfacesoftwaresupport

VariousOutputOptions
RS422,RS232,CAN,USB,and
EtherCAT
Item RFT90-6A01 RFT80-6A02 RFT80-6A01 RFT64-6A01
Product Image
Hollow Core ●
Dust Seal
Temp. Compensation ●●●
Item RFT64-SB01 RFT60-HA01 RFT44-SB01 RFT40-SA01
Product Image
Hollow Core ●
Dust Seal ●●
Temp. Compensation

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
©ROBOTOUSCo.,Ltd.www.robotous.com|[email protected]
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2.2. Power Supply Specifications
Item RFT Series
Input voltage 5V DC
Max. power consumption 0.5W
Warning Input voltage tolerance: ±10%
The F/T sensor may be damaged if input voltage exceeds the limits.
2.3. Wiring
General notices
Sensor output interface may have a different mapping between wire colors and functions. Please make sure
each wire color matches a correct function while connecting to a corresponding interface.
For CAN and RS-422, the user has to connect a terminal resistor of 120Ωfor normal operation, because the
sensor doesn’t have any terminal resistor inside.
The shield line is connected to the internal GND, so it doesn’t have to be connected to any ground outside.
For RS-232, the RX from one device should go to the TX of the other, and vice-versa.
RFT90-6A01 | RFT80-6A02 | RFT80-6A01

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RFT64-6A01 | RFT64-SB01 | RFT60-HA01 | RFT44-SB01 | RFT40-SA01

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3. Operation
3.1. F/T Sensor Output Interfaces
CAN (Control Area Network)
RS-232
RS-422
USB (Virtual COM port)
EtherCAT (with an external board (e.g., RFTEC-02), embedded for RFT80-6A02 and RFT64-6A01 only)
3.2. Communication Packets
Command Packet
To transmit commands to the F/T sensor.
To set parameters of the F/T sensor.
The size of the packet depends on sensor output interfaces, refer to Section 3.5 Packet Structure.
The size of data field is 8 bytes.
Response Packet
To receive responses from the F/T sensor.
To receive the result of data processing of the command packet
The size of the packet depends on data output interfaces, refer to Section 3.5 Packet Structure.
The size of data field is 16 bytes
3.3. Basic Operation
Notices
A user has to send the command “Start F/T Data Output” in order to measure and receive force and torque data
from the sensor. Otherwise, the F/T sensor stays idle even after applying power.
The F/T sensor can save current parameter settings which is valid even after rebooting it.
However, the sensor does not save the following commands: Start F/T Data Output, Stop F/T Data
Output, and Set Bias.
The following commands only are executable during measuring force and torque data: F/T Data Output Stop
and Set Bias.
The rest of commands are available in idle state or after executing the command of “Stop F/T Data
Output Stop”.
How to measure force & torque from the sensor with default setting
Step 1. Send the command “Start F/T Data Output” [Command ID = 11(0x0B)].
Step 2. Receive force and torque data from the sensor.
How to measure force & torque after setting parameters
Step 1. Send a command for parameter setting of the sensor. (Refer to Section 3.6 Packet Definition.)

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Step 2. Receive a corresponding response packet and check whether there was an error in processing the
command.
Step 3. Send the command “Start F/T Data Output”.
Step 4. Receive force and torque data from the sensor.
How to set a parameter while measuring force and torque.
Step 1. Send the command “Stop F/T Data Output” [Command ID = 12(0x0C)]
Step 2. Send a command for setting a parameter.
Step 3. Receive a corresponding response packet and check whether there was an error in processing the
command.
Step 4. Send the command “Start F/T Data Output”.
Step 5. Receive force and torque data from the sensor.
How to set bias while measuring force and torque
Step 1. Send the command “Start F/T Data Output” [Command ID = 11(0x0B)].
Step 2. Send the command “Set Bias” [Command ID = 17(0x11)]
Step 3. Receive force and torque data from the sensor.
3.4. Default Setting of Communication
Item
Default Values
Remarks
CAN UART
Filtering Filter OFF Filter OFF
Data Output Rate 200Hz 200Hz
Message ID
Receiver ID : 100(0x64)
Transmitter ID #1: 1(0x01)
Transmitter ID #2: 2(0x02)
N/A CAN only
Communication
Setting
CAN 2.0 A, B Compatible
Identifier: Standard Identifier
Bit Rate: 1Mbps
Size of Data: 8 Bytes
Baud Rate: 115,200bps
1 Stop Bit
No Parity
No Flow Control
Data Length: 8 Bits

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3.5. Packet Structure
3.5.1. Packet Structure of CAN Interface
The message structure of a standard CAN communication is shown in the figure above.
Maximum data field size of a CAN packet is 8 bytes.
The force/torque sensor uses the arbitration field (message ID) and data field of CAN packet.
The command packet needs a message ID to send 1 byte command to the sensor.
Receiver ID of CAN communication is a message ID for receiving commands.
The default receiver ID is 100 (0x64).
Refer to Section 3.6 Packet Definition for more information.
The response packet needs 2 message IDs to receive 16 bytes data from the sensor. In other words, it is made
of two sequential CAN packets.
Transmitter ID #1 and transmitter ID #2 are message IDs for the two sequential CAN packets,
respectively.
The default transmitter ID #1 is 1(0x01).
The default transmitter ID #2 is 2(0x02).
8 bytes data in a CAN packet with transmitter ID #1 occupies Data 1- Data 8 of the response packet
data field.
8 bytes data in a CAN packet with transmitter ID #2 occupies Data 9 – Data 16 of the response packet
data field.
3.5.2. Packet Structure of UART interface
Command Packet Structure
SOP Data Field Checksum EOP
Data 1 . . . Data 8
85(0x55) Command Data Field 170(0xAA)
Response Packet Structure
SOP Data Field Checksum EOP
Data 1 . . . Data 16
85(0x55) Response Data Field 170(0xAA)
RS-232, RS-422, and USB interfaces utilize UART communication.
UART packet structure consists of SOP (Start Of Packet), Data Field, Checksum and EOP (End Of Packet)
Message ID Data Field