Question 1

How to Fix PH EtherCAT Multi-Slave SM Mode OP Entry Failure?

Accepted Answer

TwinCAT defaults to attempting state transition without waiting for Working Counter (WcState) stability, causing slaves to detect missing output frames. This is especially common in multi-slave + SM mode. Solution: Enable "Wait for WcState is OK". This makes the master wait for all slaves' Working Counter to confirm output frame receipt before transitioning to OP, greatly reducing watchdog timeout probability.

Question 2

What Is the Torque Output Accuracy Without a Force Sensor?

Accepted Answer

PH series has undergone KT value calibration. Calibrated output torque is more accurate than directly using motor current. Without a force sensor, precise KT calibration can improve current-to-torque estimation accuracy from ±10% to within ±5%, meeting basic constant-force cleaning and collision detection needs without additional force sensors, significantly reducing costs.

Question 3

What Are the PHU Series Control Loop Frequencies?

Accepted Answer

Current loop control frequency: 16kHz; position loop: 8kHz; speed loop: 8kHz.

Question 4

PH11/48V Version Current-Related Parameter Details

Accepted Answer

1) Driver input capacitance: 33µF 2) Startup voltage increase requires BOM modification; becomes a custom product if customer requirements differ 3) Driver startup time: approximately 5ms 4) Driver enable motor voltage: 48V 5) Driver output voltage when off: 14V 6) Driver module protection voltage (excluding motor): stable under 60V; TVS cannot guarantee long-term stability above 60V; software overcurrent protection at 75V; maximum instantaneous voltage 80V 7) Single driver power consumption: 2W (standby)

Question 5

Motor Parameters Documentation (PHU/PH/PHA Series)

Accepted Answer

Please download and review the documentation for corresponding product series: https://eyoubot.com/en/documents

Question 6

What Baud Rate Can CANFD Achieve?

Accepted Answer

Default configuration: 1M arbitration frame, 5M data frame (data baud rate). Hardware layer uses CANFD; software follows traditional CANopen protocol.

Question 7

How to Fix EyouEcTestDemo Installation Failure on PH-E Series?

Accepted Answer

Solution: cd /opt/EYouEcTestDemo/bin, then directly run sudo ./EYouEcTestDemo, or add execute permission with sudo chmod +x EYouEcTestDemo.

Question 8

What Is the Maximum Voltage Rating of the PH11-E (48V)?

Accepted Answer

Maximum instantaneous voltage: 100V.

Question 9

Can the Housing Be Clamped for Mounting?

Accepted Answer

The motor housing is not recommended to bear force — it may cause deformation. A sleeve can be used instead.

Question 10

What Material Is the EYOU Joint Module Housing Made Of?

Accepted Answer

Aluminum alloy. The reducer steel wheel is steel.

Question 11

How to Close Brake Before Disabling in CAN Custom Protocol?

Accepted Answer

CAN custom protocol currently sends brake command and disable command simultaneously, but due to brake response time, disable actually takes effect first before the brake engages. In practice, send the brake command first, then send the disable command to the module. PH and PHU series modules supporting CANopen protocol have software-level control logic that brakes first then disables.

Question 12

What Are the Force Sensor Terminal and Block on PHU-F/RHU Drawings?

Accepted Answer

The terminal in front of the output side on the drawing is the force sensor interface. The block beside the drawing will be removed in the future. The two dowel pins on the drawing are for reducer and force sensor alignment, also planned for removal as they may cause noise. The rear control board connects to the force sensor — one module corresponds to one force sensor, each independently controlled.

Question 13

What Is the Maximum Position Value and Overflow Behavior?

Accepted Answer

Position mode overflows in multi-turn at ±2³¹. After reaching maximum, it wraps to the opposite minimum. Continuous rotation in position mode has issues. Speed mode supports continuous rotation, but actual position may also have drift.

Question 14

Why Does an Emergency Frame Appear When Two Masters Exist?

Accepted Answer

Two masters cannot coexist when controlling modules. Data returned after Master 2 sends commands is also received by Master 1. Since Master 1 did not send any data but received responses, the conflict causes Master 1 to issue an emergency frame — local control error.

Question 15

What Are the CANFD Arbitration and Data Domain Sampling Points?

Accepted Answer

1. CAN: data domain 75%. CAN-FD: data domain 75%, arbitration domain 80%. 2. Can be networked together, but note that our modules send/receive data in 8 bytes — exceeding this will cause error and shutdown (backward compatible, not forward compatible). This effectively only improves communication speed.

Question 16

EtherCAT Six-Axis Robotic Arm Jitter Analysis

Accepted Answer

Please refer to the EYOU-provided document: EtherCAT Integrated Module Six-Axis Collaborative Robot Arm Jitter Analysis. https://eyoubot.com/en/documents

Question 17

Does the PH Series Support Friction Compensation?

Accepted Answer

PH series currently does not support friction compensation. Compensation must be handled by the upper-level control software.

Question 18

CAN Custom Protocol Auto-Report Function (Firmware 5004+)

Accepted Answer

CAN custom protocol (firmware 5004+) supports auto-reporting: 08 4A for position and current, 08 49 for speed and current.

Question 19

What Causes Undervoltage Protection on Some Axes During Robotic Arm Operation?

Accepted Answer

1. Whether overload during operation caused high transient current pulling down bus voltage, triggering undervoltage protection. 2. Whether cable strain during motion loosened connectors, or damaged insulation caused short circuits.

Question 20

How to Manually Control PHU Series Brake via SDO?

Accepted Answer

1. Ensure firmware version is PHU V0.0.0.45 or above 2. Write 0 to 2110-00 for manual brake control Write 0 to 2111-00 to release brake; write 1 to close brake.

Question 21

Does the PD50 Discharge Resistor Apply to All Series? How to Connect?

Accepted Answer

The green terminal is for the external resistor. The white probe connects to the two ends of the internal resistor for parallel external resistor connection. When connecting, set parameters first — the CAN port does not need to be connected to the module, only the power supply is needed.

Question 22

How to Fix Orange Light Flashing and OP Entry Failure?

Accepted Answer

Module occasionally cannot enter OP mode. Switching to DC mode for OP entry is more stable.

Question 23

How to Fix 'Device Busy' or 'Open CANable Failed' in SDK?

Accepted Answer

Device or resource busy / Open CANable failed: Main cause: CANable was already opened and not closed, causing reload error. Fix 1: Call freeDLL before exiting the program — next open will succeed. Fix 2: Before each initDLL, run system command to close the device: sudo ip link set can0 down. Device doesn't support restart from bus off / Connection timed out: Cause 1: Client controller driver not supported — try a different controller. Cause 2: SDK dynamic library issue — provide joint model to get the matching library.

Question 24

How to Fix libcyhcs_log.so Error When Running PH-EC SDK?

Accepted Answer

Configure lib environment. First, write 0 to module dictionary 2004 to switch to EC mode; also close IGH when using SDK. 1. Change the interface name in the test program under the example folder to the actual network port name (check with ifconfig, replace initDll interface parameter with actual port name). Create build folder under example: mkdir build, cd build, cmake .., make to recompile. 2. Run under sudo: execute sudo su 3. Set lib environment: export LD_LIBRARY_PATH=/home/xxx/eyou_ethercat_sdk_x86_64_linux_gnu/lib (replace with your actual path)

Question 25

How to Fix PHU Stuttering During Operation?

Accepted Answer

Increase the load inertia ratio (P00.0F), adjustable to 5-10.

Question 26

How to Upgrade PHU Series Firmware via FOE?

Accepted Answer

Use TwinCAT master, switch state to Boot mode. Enter product name: eyou, password: 87654321. Click Init to initialize. Import the efw format firmware file.

Question 27

How to Fix CAN Port Not Opening on Chuangxin Technology Pro Device?

Accepted Answer

Our host software is developed based on the Chuangxin Technology CANpro protocol analysis platform package. If the CAN port cannot be opened, the likely cause is that Chuangxin's package has been updated and needs manual replacement. 1. Download the CANpro protocol analysis platform bundled with the Chuangxin installer, locate the file directory 2. Replace the ControlCAN.dll in our host software with the one from that directory

Question 28

General Troubleshooting for SDK setOperateMode Failed

Accepted Answer

Mode setting is the very first step. If it fails from the start, consider: 1. Whether motor ID matches and baud rate is set correctly; 2. Whether the termination resistor on USB-to-CAN is enabled, ensuring 60-ohm bus resistance; 3. Check if communication is functioning normally.

Question 29

How to Fix PHU Series IGH Master Cannot Enter OP?

Accepted Answer

Use SDO in IGH: write 1 to PHU dictionary 2100, then write 1 to dictionary 2130 to save, switching to EC mode. sudo su and set path: export LD_LIBRARY_PATH=path RPDO index: write 0x1600 (customer was using 1603) TPDO index: write 0x1a00

Question 30

Which PH Series Models Support CANopen and Which Support CANFD?

Accepted Answer

PH20-C, PH25-C currently support both CANopen and CANFD protocols. PH14-C, PH17-C have CANFD boards available — customers can specify CANFD protocol. PH08, PH11: only the Zhiyuan version (no brake) supports CANFD.

Question 31

Why Can't PHU and PH-E Series Be Controlled in CSP Mode?

Accepted Answer

PH-E or PHU must enable DC mode for CSP operation, otherwise it will not run. Sync cycle can be set to 2ms.

Question 32

How to Troubleshoot 'setOperateMode Failed' When Calling the SDK?

Accepted Answer

Cause 1: SDK example code defaults module ID to 1 — it must match the actual module ID (in case the customer has changed it) Cause 2: The 120-ohm DIP switch on CANable (EYOU USB-CAN debug board) must be switched to ON beforehand (otherwise communication may fail and trigger the error)

Question 33

How to Fix PH-E Series Occasional OP Entry Failure on Frequent Master Restarts?

Accepted Answer

1. Set data send frequency to 500µs before entering OP (adjust based on actual module count on the bus) 2. Switch to DC mode in IGH master (OP will be more stable)

Question 34

What Are the PHU Output Position, Speed, and Torque Formulas?

Accepted Answer

Target Position (pulses) ÷ 524,288 ÷ Reduction Ratio × 360° = Target Position (degrees) Target Speed (pulses) ÷ 524,288 ÷ Reduction Ratio × 60 = Target Speed (rpm) Output Torque = Current × Coefficient × Reduction Ratio × Efficiency Loss (efficiency loss is difficult to control, result may not be accurate)

Question 35

Can CANFD Modules Be Mixed with CANopen or CAN Custom Modules?

Accepted Answer

CANFD and CANopen modules can be used together, but communication is limited to CANopen's 8 bytes with maximum 1000kHz baud rate. CANFD and CAN custom modules cannot be mixed — protocols must be unified.

Question 36

Is There a Position Overflow Limit for PH Series in Position Mode?

Accepted Answer

Yes, see the diagram below for specific overflow ranges.

Question 37

What Is the Minimum Control Cycle for EC Version Modules?

Accepted Answer

EC mode minimum control cycle is 1ms.

Question 38

Why Does Force Control Mode Switching Fail on PHU20?

Accepted Answer

Force control requires the FHU model, which includes a torque sensor.

Question 39

Can Speed Be Limited in Torque Mode?

Accepted Answer

Speed cannot be limited in torque mode — the motor runs at maximum speed. You can try limiting torque in speed mode.

Question 40

Does the Host Software Support ARM Architecture?

Accepted Answer

Host software currently not supported (as of 2025.12.27).

Question 41

Why Do Some Motors Stutter in IP Mode on the Same Bus?

Accepted Answer

1. Communication issue — high bus load causing data loss 2. Timer instability under high system load causing jitter 3. Unreasonable trajectory planning with excessive acceleration/deceleration at certain points 4. Improper motor PID parameters. Troubleshoot these issues.

Question 42

How to Set the Zero Point of a Harmonic Motor via Code?

Accepted Answer

Ensure the motor has not exceeded single-turn range before this operation — power cycle the motor if needed. Steps: clear existing offset and read the actual position after clearing; write the negative of the read position as the offset; save to firmware (parameter 0x65766173). Refer to the SDK for specific code.

Question 43

What Is the Maximum Status Report Frequency for Harmonic Motors?

Accepted Answer

Maximum frequency can reach 1000Hz.

Question 44

How to Read the Second Encoder on PHU Series?

Accepted Answer

1. EtherCAT CoE: read dictionary 0x2771:00 (int32) 2. Host software: read P07.72

Question 45

What Is the Moment of Inertia for Each Planetary Series Model?

Accepted Answer

PP08/PP08D: 9.8626×10⁻⁷ kg·m²; PP11/PP11D: 7.7384×10⁻⁶ kg·m²

Question 46

How to Bind CANable Device Name in the SDK?

Accepted Answer

Not supported on Windows. For Linux binding method, see the linked document.

Question 47

What Is the ESD Protection Level of Joint Modules?

Accepted Answer

Contact discharge: 4kV; air discharge: 8kV.

Question 48

How to Calculate Output Torque from Motor KT?

Accepted Answer

To calculate using motor-side KT, refer to the linked technical document for modifications, then use the formulas provided in the document.

Question 49

Why Does MIT Function Fail When Motor ID Is Set to a Large Value?

Accepted Answer

This was mainly due to a host software issue, which has been updated. Version 251106 and later.

Question 50

Is It Abnormal to See Torque Value 30 on Host Software When Powered but Not Enabled?

Accepted Answer

When the motor is powered on but not enabled, actual torque will show a small value — this does not affect operation. The main reason: when only powered on but not enabled, the internal motor is not energized; the torque value is due to control board hardware fluctuation and does not affect use. After enabling, the actual torque reflects the motor output. If concerned, compensation can be applied per the method shown in the image.

Question 51

Are There Torque Requirements for Screw Fastening Between Joint Modules and Structural Parts?

Accepted Answer

Smaller screws have no national standard to reference. Consult the fastener manufacturer for the destruction torque; generally use 60% of the destruction torque as the tightening torque.

Question 52

Can the 05 Fast Write Command Send Data Continuously in CAN Custom Protocol?

Accepted Answer

The 05 fast write command can be used to send data to the motor, but delays are needed when sending large amounts of data. However, 05 is generally not recommended — the difference is that 01 returns data, allowing confirmation of receipt and troubleshooting of communication issues.

Question 53

What Is the Relationship Between the First and Second Encoder Values?

Accepted Answer

First encoder increment ÷ reduction ratio = second encoder increment.

Question 54

What Is the Static Holding Power of the PH20/PH25 Power-off Brake?

Accepted Answer

At 48V supply, brake locked state is 2.25W, brake released state is 4.4W.

Question 55

What Is the Input Capacitance for Each Joint Module Model?

Accepted Answer

PP08 input capacitance: 68µF; PP08D: 28µF; PH20 and PH25: 83µF; PHU20, PHU17, PHU14: 210µF.

Question 56

What Happens If a New Position Is Sent While the Motor Is Still Moving?

Accepted Answer

The motor will move directly to the new position value.

Question 57

What Is the Pole Pair Count for PH Series Motors?

Accepted Answer

PH08 and PH11 modules have 5 pole pairs; PH14, PH17, PH20, and PH25 modules have 8 pole pairs.

Question 58

What to Do If Overvoltage Protection Triggers After Firmware Upgrade?

Accepted Answer

The old motor's control board voltage reading is inaccurate and reads high. Change the value of 202d:03 to exceed the displayed voltage, then restart the motor.

Question 59

What Is the Torque Conversion Formula for CAN Custom Protocol Motors?

Accepted Answer

Before firmware V5003: Motor phase current (mA) = 0x05 index value (Iq) × corresponding coefficient Coefficients by model: PP05/PP08/PP08D: ×1.24; PH08/PH08D/PH08M: ×2.47; PP11/PP11D/PP11L: ×8.95; PH11/PH11D: ×5.37; PH14/PH17: ×7.67; PH20/PH25: ×13.43 Firmware V5003 and later: Output torque (N.m) = 0x05 index value (‰) / 1000 × reducer Rated Torque Iq value = 0x05 index value × 0x53 index value / 1000 Motor phase current (mA) = Iq value × corresponding coefficient (same as above)

Question 60

Does the SDK Have a C Language Dynamic Library?

Accepted Answer

The dynamic library is exported in C. When using with C, some header file syntax may be incompatible and may need adjustment.

Question 61

How to Set the Zero Point on PHU Series?

Accepted Answer

1. Host software: enter homecmd in developer mode and press Enter 2. ECAT master: set mode 0x6060=6, 0x6040=0x10, current position becomes zero, save with 0x2130=1 3. SDK: refer to Test-zero in the SDK

Question 62

Is the 10000 Count Displayed in PHU Position Mode a Pulse Value?

Accepted Answer

Yes.

Question 63

What Is the Resolution and Pulse Count Per Revolution of the PHU Series?

Accepted Answer

PHU series resolution is 19-bit. Pulse count per revolution (360°) = 524,288 × reduction ratio.

Question 64

What Type of Brake Is Used?

Accepted Answer

Friction-type permanent magnet brake.

FAQ

Do Planetary and Harmonic Joints Have a Power-off Brake?

What Are the Communication Methods for Planetary and Harmonic Joints?

Why Does the Harmonic Motor Have Dual Encoders?

Does the Motor Include a Built-in Driver?

What Is the Difference Between Single-Shaft and Dual-Shaft?

What Is the Accuracy of Planetary and Harmonic Motors?

What Is the Protection Rating of the Joint Motor?

What Is the Function of the GH1.25 Terminal?

What Is the Maximum Current for the Distribution Board (1-to-4)?

Where Is the Load Mounted?

What Material Are the Planetary Gears and Harmonic Flexspline Made Of?

Are the Encoders Absolute? What Type Is the Power-off Brake? What Is the Resolution?

What Is the Repeatability Positioning Accuracy of the PH08-C?

Is There a 3-Pin to RJ45 Adapter Available?

Can a Slip Ring Be Added to the PP05?

Can the Joint Motor Be Used to Build a Gimbal?