ETEL DSC2P/DSC2V Servo Controller Debugging Guide

Guide to On site Debugging and Troubleshooting of ETEL DSC2P/DSC2V Series Digital Position Controllers

In the field of precision motion control, ETEL direct drive technology holds an important position in cutting-edge industries such as semiconductor manufacturing, precision machine tools, optical inspection, and life sciences due to its high dynamic response and high-precision positioning capabilities. Its DSC series digital position controller (including single axis DSC2P/DSC2V and dual axis DSCDP/DSCDL/DSCDM), combined with a proprietary Turbo TEL Bus (TEB) communication network, can achieve multi axis synchronization and interpolation motion. However, the debugging threshold for such highly integrated servo systems is relatively high. From initial power on, motor initialization (Phasing), zeroing (Homing) to regulator parameter tuning, any parameter mismatch at any stage can lead to system errors or even motor runaway. This article combines the core content of the DSC series operation and software manual (version F) to extract the most common fault phenomena and their troubleshooting strategies in on-site debugging, providing engineers with a practical reference for grounding gas.

Initial power on and communication establishment (ETEL Tools connection)

The DSC series controller communicates with the upper computer through the EBL2 (ETEL Bus Lite 2) protocol, with a default baud rate of 115200 bps. If using a single axis independent configuration, connect the PC serial port to the controller EBL2 port, open the ETEL Tools (ETT) software, and select the corresponding COM port in the Connection Chooser.

Typical fault: Communication cannot be established, and the status bar displays "Disconnected".

Troubleshooting steps:

Confirm that the PC serial port is not occupied by other software (such as terminal debugging tools).

Check if the LCD display screen of the controller has completed the self-test normally (such as displaying "DSC2P READY"). If there are no characters or abnormal display on the screen, it may be a power supply issue or hardware failure.

If you need to modify the baud rate, set it through parameter K195 (values 0/9600/19200/38400/57600/115200 correspond to different rates), execute SAV.<axis>=2 to save to Flash, and it will take effect after power failure and restart. The manual specifically states that K195 can only be read when powered on for the first time, and must be powered off and back on after modification.

In a multi axis configuration, the controller is connected through a TEB daisy chain, and the axis number is set by DIP switches or AXI commands. If there is a "BAD NOTE TEB ERR" (M64=59), it indicates that there are duplicate axis numbers on the TEB ring. It is necessary to check the DIP switch of each controller or reassign a unique axis number through AXI command (DSCDP/DSCDL/DSCDM are dual axis controllers, the first axis number must be even, and the second one automatically+1).

2、 Drive Setting and Motor/Encoder Selection

When using ETEL Tools for the first time, be sure to complete the system configuration through the "Drive Setting" tool. This process guides users step by step to select the controller model, motor model, encoder type, initialization mode, zeroing mode, and load mass/inertia.

2.1 Motor parameter errors leading to abnormal current

Section 8.3.2 of the manual states that if the motor model is selected incorrectly, the current limit and protection parameters (such as K83 overcurrent threshold, K84/K85 I ² t limit) will not match, which may result in motor winding burnout or controller overcurrent alarm (M64=2/3). If using a non ETEL standard motor, it is necessary to select "Other" and manually input peak current, continuous current, inductance, resistance, and back electromotive force constant (Ku).

Key parameters:

K240 (motor type): 0=linear motor, 1=rotary motor. This parameter affects the display conversion of position/velocity units in ETEL Tools.

K89 (number of phases and PWM frequency): For DSC2P, the typical value is 30 (three-phase, 24kHz PWM); For high inductance motors, 11/21/31 (12kHz PWM) can be selected. K89 error will result in "K89 BAD VALUE" (M64=41), and this parameter is only read when the controller is powered on. After modification, SAV and restart are required.

2.2 Encoder Configuration and Interpolation Factor (K77)

The interpolation factor of the simulated sine cosine encoder (1Vpp) is determined by parameter K77, with a range of 0-4 (DSC2P/DSC2V/DSCDP/DSCDM) or 0-7 (DSCDL), corresponding to 8-15 bit interpolation. The larger the K77, the higher the position resolution, but the maximum speed is limited by the controller calculation period (FTI). If K77 is set too high and causes position data overflow, it will trigger "ENCODER POS LOST" (M64=21) or "ENDAT OVERFLOW" (M64=16, for EnDat encoder).

On site experience: For most linear motor applications, K77=3 (11 bit interpolation) can provide sub micron resolution while ensuring sufficient tracking speed. If there is high-frequency vibration during motor operation, you can try reducing K77 or adjusting the encoder signal offset/amplitude correction parameters (K70~K73).

Phasing fault diagnosis during initialization

Brushless motors (including ETEL core and coreless linear motors) must undergo initialization (Phasing) upon initial power on to determine the initial electrical angle of the rotor relative to the stator poles. If initialization fails, the motor will not be able to output normally or experience "runaway".

3.1 K90=2 (constant current initialization) common problems

This is the most commonly used initialization method, suitable for most iron core and iron core less motors. During initialization, the controller injects a constant current into the motor winding to move the rotor (or rotor) to a stable equilibrium point, with a movement distance not exceeding one magnetic pole cycle (usually 32mm). The parameters K92 (constant current amplitude) and K94 (initialization time) are crucial.

Fault 1: During the initialization process, the motor does not move or moves very little, and then reports "Initialize LOW CUR" (M64=153) or "TIMEOUT AUT CMD" (M64=156).

Reasons and Countermeasures:

K92 is set too low, and the electromagnetic force is insufficient to overcome static friction. K92 can be gradually increased (but not exceeding the incremental value corresponding to the peak current of the motor).

The K94 time is too short, and the motor has not yet reached a stable equilibrium point. The typical value is 5000 (corresponding to 5 seconds), which can be increased to 10000~15000 for large inertia loads.

If the motor is equipped with a brake, it is necessary to confirm that the brake has been released (controlled through digital output).

Fault 2: During initialization, the motor moves too far (exceeding ± 20% of the magnetic pole period), and reports "Initialize HIGH CUR" (M64=154).

Reason and countermeasures: K92 is too high, causing the rotor to rush over multiple equilibrium points. The K92 value should be reduced or the "small displacement initialization" mode (K90=6) should be enabled.

3.2 Application of K90=6 (small displacement initialization)

For vertical axis or high friction systems, constant current initialization may cause the load to slide or impact the mechanical limit. Small displacement initialization measures the position of the motor through short-term pulse current measurement, with almost no visible movement. This mode depends on parameters K91 (pulse current amplitude) and K101 (pulse interval time).

Debugging tip: It is recommended to set K91 to around 5% of K60 (force/torque limit) initially, and gradually increase it if it reports "Initial LOW CUR"; If it reports' Initial LOW TIME '(M64=155), K101 should be increased to extend the pulse interval, especially for high inertia systems, giving the motor enough time to respond to pulse excitation.

3.3 Phase reversal (K56) and AUT command

If the output direction of the motor is opposite to the command after initialization, or if K53 (phase adjustment value) cannot converge, it is usually necessary to execute AUT.<axis>=10 (bit1+bit3) to automatically calculate K56 (phase sequence reversal) and K53 (fine phase adjustment). Section 12.8 of the manual states that the AUT command is only executed in the "Power Off" state, and during the execution process, the controller will briefly move the motor to find the optimal pointer position for the commutation meter.

Attention: For iron core less motors, the current loop gain K80 calculated by AUT may not be accurate (as explicitly stated in the manual). In this case, K80 and K81 (current loop proportional/integral gain) should be manually adjusted.

Homing mode selection and exception handling

Return to zero (IND command) is used to establish the origin of the mechanical coordinate system. The ETEL controller offers up to 40 zeroing modes (K40), including mechanical limit switches, origin switches, encoder reference pulses (Index), and their combinations.

4.1 Zero return timeout or collision limit

The most common error is "SING IDX SEARCH" (M64=62) or "MULT IDX SEARCH" (M64=61), indicating that the reference pulse was not found within the specified search range. At this point, it is necessary to check:

K41 (zeroing speed) and K42 (zeroing acceleration): If the speed is too fast, the encoder may miss the Index pulse. Suggest setting K41 to 10%~20% of the rated speed.

K43 (limit detection tracking error) and K44 (limit detection force limit): If the tracking error or torque exceeds the set value before the mechanical limit is triggered, the controller will mistakenly believe that the hard limit has been reached and stop the search. Ensure that K43>50% of K30 (tracking error limit) and K44<80% of K60 (force limit).

For multi reference pulse encoders (such as Heidenhain LIDA series), the parameter K75 (reference pulse spacing) must be precisely set, otherwise multi pulse decoding will fail.

4.2 Zeroing completed, but the accuracy of the original point repetition is poor

If the deviation of the origin position after each zeroing exceeds several incremental units, the possible reasons may be:

Return to zero direction setting error (K40's "positive"/"negative" does not match the encoder Index signal edge).

Fine phase adjustment (K52=1) is not enabled. After activation, the controller will replace the phase obtained from this initialization with K53 (the phase value pre measured by the AUT command) each time the zeroing is completed, ensuring that the electrical angle is consistent with each power on.

If using the combination mode of Home switch and Index (such as K40=34/35), it is necessary to correctly configure the polarity reversal of K58 (limit/origin switch signal source selection) and K32 (bit1 reverse Home switch, bit2 reverse encoder limit).

Parameter tuning of regulator and vibration suppression

The DSC series adopts a state space position regulator (equivalent PID)+PI current regulator. Beginners should use the "Scope" tool of ETEL Tools to iteratively optimize parameters by observing the waveforms of position (M7), velocity (M11), and current (M20/M21) through step movement.

5.1 Current loop regulation (K80/K81)

The current loop is the inner loop of the system, and its bandwidth should be much higher than that of the position loop. Automatic tuning of AUT usually provides a good initial value, but if there is current oscillation or large current tracking error, it can be manually adjusted:

K80 (Proportional Gain): Increasing K80 can accelerate current response, but if it is too high, it can cause current ripple or amplification of switch noise.

K81 (Integral Gain): Used to eliminate steady-state current errors, but excessive gain can cause overshoot or oscillation of the current loop.

5.2 Position ring adjustment (K1/K2/K4)

The position loop parameters directly affect the positioning accuracy and dynamic characteristics:

K1 (Proportional Gain): Increasing K1 can reduce tracking error, but if it is too large, it can cause overshoot. Observe the step response. If the overshoot is greater than 10%, reduce K1 or increase K2.

K2 (velocity feedback gain, equivalent derivative): Increasing K2 can suppress overshoot and oscillation, but it will reduce system stiffness. A balance needs to be struck between rigidity and stability.

K4 (Integral Gain): Used to eliminate static position errors. When K4=0, the system is purely proportional control and there is steady-state error; Gradually increase K4 until the error returns to zero, but pay attention to integral saturation (anti windup controlled by K5/K6).

5.3 Feedforward compensation (K20/K21) and filters (K8/K9)

To improve high-speed tracking accuracy, speed feedforward (K20) and acceleration feedforward (K21) can be enabled. Usually, the initial value of K20 is set to 70%~100% of K2, and K21 is set as the value related to the system inertia ratio. If the position curve appears concave or convex during acceleration and deceleration, K21 compensation can be adjusted.

For mechanical resonance (manifested as high-frequency howling from 500Hz to 1kHz), low-pass filter K8 (velocity feedback filtering) or K9 (force reference filtering) can be used. The cut-off frequency calculation formula for K8/K9 can be found in Section 13.1.2.3 of the manual. The typical starting value is 10-50, and the lower the frequency, the stronger the filtering effect but the greater the phase lag.

Synchronous startup and debugging of digital I/O and STI

The DSC controller provides digital input (DIN)/output (DOUT) for interaction with external PLCs or sensors. Especially when multiple axes need to start synchronously, using the STI command in conjunction with K160~K164 parameters can achieve the logic of "waiting for external trigger signals - starting motion simultaneously".

Typical fault: STI triggers rear axle immobility, reporting "SYNC HRO START" (M64=63).

Troubleshooting:

Check if K160 (DIN mask) and K161 (required level state) match the actual wiring. For example, if DIN1 is used as the trigger, K160=1 and K161=1 indicate waiting for the rising edge of DIN1.

Check K164 (timeout, unit STI). If the trigger signal does not arrive within the timeout period, the controller will report an error. For DSC2P/DSC2V, STI=166.67 μ s; For DSCDP/DSCDL/DSCDM, STI=500 μ s. Reasonable settings should be made based on the response time of external signals (e.g. K164=6000 corresponds to approximately 1 second).

Confirm that the controller is in "Power On" and there are no other errors (such as limit triggering).

Parameter Save (SAV) and Curing

After all parameter adjustments are completed, it is necessary to execute SAV.<axis>=2 to save the K, X, E, R, F parameters and axis numbers to Flash, otherwise the parameters will be lost after power failure. If you need to save the sequence (S register) and lookup table (L), use SAV.<axis>=0.

Attention: During the execution of the SAV command, the controller sequence execution will briefly stop, and the manual warns that the SAV command will cause the controller to perform a save operation (M64=190), which is a normal prompt message and not a fault.

On site rapid fault comparison table

Possible causes of malfunction: refer to parameters/commands for priority handling

After power on, there is no display on the LCD. The power supply is missing or the fuse is damaged. Check the main power supply and F7 fuse

Communication cannot connect, baud rate mismatch or serial port occupied K195. Confirm K195=0 (115200) and restart

Initialization motor does not move, K92 current is too low or the brake is not opened. K94 increases K92 and releases the brake

Initialize flying car K92 too high or in reverse phase (K56) K92, K56 lowers K92, execute AUT=10

Return to zero collision limit K43/K44 sensitivity is too high K43, K44 increases K43, decreases K44

Position overshoot is too high for K1 or too low for K2. K1 decreases and K2 increases

Motor high-frequency whistling, mechanical resonance, or high current loop gain. K8, K9, K80. Increase K8 or K9 filtering

STI triggers unresponsive DIN logic or timeout setting error K160, K161, K164. Check DIN level and increase K164