Basic settings

Check before operation

Table 6-1 Check contents before operation

Power-on

Connect the main circuit power supply

After power on the main circuit, the bus voltage indicator shows no abnormality, and the panel display "rdy", indicating that the servo drive is in an operational state, waiting for the host computer to give the servo enable signal.

If the drive panel displays other fault codes, please refer to “10 Malfunctions"” to analyze and eliminate the cause of the fault.

Set the servo drive enable (S-ON) to invalid (OFF)

Jog operation

Jog operation is used to judge whether the servo motor can rotate normally, and whether there is abnormal vibration and abnormal sound during rotation. Jog operation can be realized in two ways, one is panel jog operation, which can be realized by pressing the buttons on the servo panel. The other is jog operation through the host computer debugging platform.

Panel jog operation

Enter “P10-01” by pressing the key on the panel. After pressing “OK”, the panel will display the current jog speed. At this time, you can adjust the jog speed by pressing the "up" or "down" keys; After adjusting the moving speed, press "OK", and the panel displays "JOG" and is in a flashing state. Press "OK" again to enter the jog operation mode (the motor is now powered on!). Long press the "up" and "down" keys to achieve the forward and reverse rotation of the motor. Press "Mode" key to exit the jog operation mode. For operation and display, please refer to "5.3.2. Jog operation".

Jog operation of servo debugging platform

Open the jog operation interface of the software “Wecon SCTool”, set the jog speed value in the "set speed" in the "manual operation", click the "servo on" button on the interface, and then achieve the jog forward and reverse function through the "forward rotation" or "Reverse" button on the interface. After clicking the "Servo off" button, the jog operation mode is exited. The related function codes are shown below.

Table 6-2 JOG speed parameter

Rotation direction selection

By setting the “P00-04” rotation direction, you could change the rotation direction of the motor without changing the polarity of the input instruction. The function code is shown in below.

Table 6-3 Rotation direction parameters 

Braking resistor

The servo motor is in the generator state when decelerating or stopping, the motor will transfer energy back to the drive, which will increase the bus voltage. When the bus voltage exceeds the braking point, The drive can consume the feedback energy in the form of thermal energy through the braking resistor. The braking resistor can be built-in or externally connected, but it cannot be used at the same time. When selecting an external braking resistor, it is necessary to remove the short link on the servo drive.

The basis for judging whether the braking resistor is built-in or external.

1. the maximum brake energy calculated value > the maximum brake energy absorbed by capacitor, and the brake power calculated value ≤ the built-in braking resistor power, use the built-in braking resistor.
2. the maximum brake energy calculated value > the maximum brake energy absorbed by capacitor, and the brake power calculated value > the built-in braking resistor power, use external braking resistor.

Table 6-4 Braking resistor parameters

Servo operation

Set the servo enable (S-ON) to valid (ON)

The servo drive is in a running state and displays "run", but because there is no instruction input at this time, the servo motor does not rotate and is locked.

S-ON can be configured and selected by the DI terminal function selection of the function code "DIDO configuration".

Input the instruction and the motor rotates

Input appropriate instructions during operation, first run the motor at a low speed, and observe the rotation to see if it conforms to the set rotation direction. Observe the actual running speed, bus voltage and other parameters of the motor through the host computer debugging platform. According to "7 Adjustment", the motor could work as expected.

Timing diagram of power on

Servo shutdown

According to the different shutdown modes, it could be divided into free shutdown and zero speed shutdown. The respective characteristics are shown in Table 6-5. According to the shutdown status, it could be divided into free running state and position locked, as shown in Table 6-6.

Table 6-5 Comparison of two shutdown modes

Table 6-6 Comparison of two shutdown status

Servo enable (S-ON) OFF shutdown

The related parameters of the servo OFF shutdown mode are shown in the table below.

Table 6-7 Servo OFF shutdown mode parameters details

Emergency shutdown

It is free shutdown mode at present, and the motor shaft remains in a free state. The corresponding configuration and selection could be selected through the DI terminal function of the function code "DIDO configuration". The V1.18 firmware version adds the Estop stop time setting function. In some occasions where the servo needs to control the emergency stop of the motor, it is necessary to control the emergency stop time of the DI. Therefore, the P01-05 shutdown deceleration time function is added to deal with this situation.

Estop mode 1 (deceleration stop):

1. Configurate DI function code: 8 [ESTOP]

2. Set P1-5 shutdown deceleration time.

3. Trigger DI emergency shutdown.

4. Servo emergency shutdown and deceleration to zero speed.

Estop mode 2:

1. Configurate DI function code: 1 [Servo enable SON]

2. Set P1-05 shutdown deceleration time.

3. Set P0-05 Servo OFF shutdown mode: zero speed stop.

4. Trigger DI to turn off servo enable SON.

Overtravel shutdown

Overtravel means that the movable part of the machine exceeds the set area. In some occasions where the servo moves horizontally or vertically, it is necessary to limit the movement range of the workpiece. The overtravel is generally detected by limit switches, photoelectric switches or the multi-turn position of the encoder, that is, hardware overtravel or software overtravel.

Once the servo drive detects the action of the limit switch signal, it will immediately force the speed in the current direction of rotation to 0 to prevent it from continuing, and it will not be affected for reverse rotation. The overtravel shutdonw is fixed at zero speed and the motor shaft remains locked.

The corresponding configuration and selection could be selected through the DI terminal function of the function code "DIDO configuration". The default function of DI3 is POT and DI4 is NOT, as shown in the table below.

Table 6-8 DI3 and DI4 channel parameters

(4) Malfunction shutdown

When the machine fails, the servo will perform a fault shutdown operation. The current shutdown mode is fixed to the free shutdown mode, and the motor shaft remains in a free state.

Brake device

The brake is a mechanism that prevents the servo motor shaft from moving when the servo drive is in a non-operating state, and keeps the motor locked in position, so that the moving part of the machine will not move due to its own weight or external force.

Wiring of brake device

The brake input signal has no polarity. User need to prepare a 24V power supply. The standard connection of brake signal BK and brake power supply is shown in the figure below. (take VD2B servo drive as example)

Brake software setting

For a servo motor with brake, one DO terminal of servo drive must be configured as function 141 (BRK-OFF, brake output), and the effective logic of the DO terminal must be determined.

Related function code is as below.

Table 6-2 Relevant function codes for brake setting

Table 6-9 Brake setting function codes

According to the state of servo drive, the working sequence of the brake mechanism can be divided into the brake sequence in the normal state of the servo drive and the brake sequence in the fault state of the servo drive.

Servo drive brake timing in normal state

The brake timing of the normal state could be divided into: the servo motor static (the actual speed of motor is lower than 20 rpm) and servo motor rotation(the actual speed of the motor reaches 20 and above).

• Brake timing when servo motor is stationary

When the servo enable changes from ON to OFF, if the actual motor speed is lower than20 rpm, the servo drive will act according to the static brake sequence. The specific sequence action is shown in Figure 6-3

• The brake timing when servo motor rotates

When the servo enable is from ON to OFF, if the actual motor speed is greater than or equal to 20 rpm, the drive will act in accordance with the rotation brake sequence. The specific sequence action is shown in Figure 6-4.

Brake timing when the servo drive fails

The brake timing (free shutdown) in the fault status is as follows.

Position control mode

Position control is the most important and commonly used control mode of the servo system. Position control refers to controlling the position of the motor through position instructions, and determining the target position of the motor by the total number of position instructions. The frequency of the position instruction determines the motor rotation speed. The servo drive can achieve fast and accurate control of the position and speed of the machine. Therefore, the position control mode is mainly used for occasions that require positioning control, such as manipulators, mounter, engraving machines, CNC machine tools, etc. The position control block diagram is shown in the figure below.

Set “P00-01” to 1 by the software “Wecon SCTool”, and the servo drive is in position control mode.

Table 6-10 Control mode parameters

Position instruction input setting

When the VD2 series servo drive is in position control mode, firstly set the position instruction source through the function code “P01-06”.

Table 6-12 Position instruction source parameter

The source of position instruction is pulse instruction (P01-06=0)

Low-speed pulse instruction input

Figure 6-7 Position instruction input setting

VD2 series servo drive has a set of pulse input terminals to receive the input of position pulse (via the CN2 terminal). The position pulse mode connection is shown in Figure 6-7.

The instruction pulse and symbol output circuit on the control device(HMI/PLC) side could select differential input or open collector input. The maximum input frequency is shown as below.

Table 6-13 Pulse input specifications

• Differential input

Take VD2A and VD2B drive as examples, the connection of differential input is shown as below.

• Open collector input

Take VD2A and VD2B drive as examples, the connection of differential input is shown as below.

• Position pulse frequency and anti-interference level

When low-speed pulses input pins, you need to set a certain pin filter time to filter the input pulse instructions to prevent external interference from entering the servo drive and affecting motor control. After the filter function is enabled, the input and output waveforms of the signal are shown in Figure 6-10.

The input pulse frequency refers to the frequency of the input signal, which can be modified through the function code “P00-13”. If the actual input frequency is greater than the set value of “P00-13”, it may cause pulse loss or alarm. The position pulse anti-interference level can be adjusted through the function code “P00-14”, the larger the set value, the greater the filtering depth. The details of related function code parameters are as shown below.

Table 6-14 Position pulse frequency and anti-interference level parameters

Table 6-15 VD2L Position pulse frequency and anti-interference level parameters

• Position pulse type selection

In VD2 series servo drives, there are three types of input pulse instructions, and the related function codes are shown in the table below.

Table 6-15 Position pulse type selection parameter

Pulse type selection	Pulse type	Signal	Schematic diagram of forward pulse	Schematic diagram of negative pulse
0	Direction + pulse (Positive logic)	PULSE SIGN
1	CW/CCW	PULSE (CW) SIGN (CCW)
2	AB phase orthogonal pulse (4 times frequency)	PULSE (Phase A) SIGN (Phase B)	Phase A is 90° ahead of Phase B	Phase B is 90° ahead of Phase A
3	Direction + pulse (Negative logic)	PULSE SIGN
4	CW/CCW (Negative logic)	PULSE (CW) SIGN (CCW)
5	AB phase orthogonal pulse (4 times frequency negative logic)	PULSE (Phase A) SIGN (Phase B)	Phase B is ahead of A phase by 90°	Phase A is ahead of B phase by 90°

Table 6-16 Pulse description

The source of position instruction is internal position instruction (P01-06=1)

The VD2 series servo drive has a multi-segment position operation function, which supports maximum 16-segment instructions. The displacement, maximum operating speed (steady-state operating speed) and acceleration/deceleration time of each segment could be set separately. The waiting time between positions could also be set according to actual needs. The setting process of multi-segment position is shown in Figure 6-11.

The servo drive completely runs the multi-segment position instruction set by P07-01 once, and the total number of positions is called completing one round of operation.

• Set multi-segment position running mode

Table 6-17 multi-segment position running mode parameters

VD2 series servo drive has three multi-segment position running modes, and you could select the best running mode according to the site requirements.

1. Single running

In this running mode, the segment number is automatically incremented and switched, and the servo drive only operates for one round (the servo drive runs completely once for the total number of multi-segment position instructions set by P07-02 and P07-03). The single running curve is shown in Figure 6-12, and S1 and S2 are the displacements of the 1st segment and the 2nd segment respectively

• 2. Cycle running

In this running mode, the position number is automatically incremented and switched, and the servo drive repeatedly runs the total number of multi-segment position instructions set by P07-02 and P07-03. The waiting time could be set between each segment. The cycle running curve is shown in Figure 6-13, and S1,S2,S3 and S4 are the displacements of the 1st, 2nd, 3rd and 4th segment respectively.

3. DI switching running

In this running mode, the next running segment number could be set when operating the current segment number. The interval time is determined by the instruction delay of the host computer. The running segment number is determined by DI terminal logic, and the related function codes are shown in the table below.

Table 6-18 DI function code

The multi-segment segment number is a 4-bit binary number, and the DI terminal logic is level valid. When the input level is valid, the segment selection bit value is 1, otherwise it is 0. Table 6-17 shows the correspondence between the position bits 1 to 4 of the internal multi-segment position and the position number.

Table 6-20 INPOS corresponds to running segment number

The operating curve in this running mode is shown in Figure 6-14.

VD2 series servo drives have two margin processing methods: run the remaining segments and run from the start segment again. The related function code is P07-04.

Run the remaining segments

In this processing way, the multi-segment position instruction enable is OFF during running, the servo drive will abandon the unfinished displacement part and shutdown, and the positioning completion signal will be valid after the shutdown is complete. When the multi-segment position enable is ON, and the servo drive will start to run from the next segment where the OFF occurs. The curves of single running and cycle running are shown in Figure 6-15 and Figure 6-16 respectively.

Run again from the start segment

In this processing mode, when the multi-segment position instruction enable is OFF during running, the servo drive will abandon the uncompleted displacement part and shutdown. After the shutdown is completed, the positioning completion signal is valid. When the multi-segment position enable is ON, and the servo drive will start to operate from the next position set by P07-02. The curves of single running and cycle running are shown in Figure 6-17 and Figure 6-18 respectively.

VD2 series servo drives have two types of displacement instructions: relative position instruction and absolute position instruction. The related function code is P07-05.

• Relative position instruction

The relative position instruction takes the current stop position of the motor as the start point and specifies the amount of displacement.

• Absolute position instruction

The absolute position instruction takes "reference origin" as the zero point of absolute positioning, and specifies the amount of displacement.

• Multi-segment position running curve setting

The multi-segment position running supports maximum 16 segments different position instructions. The displacement, maximum running speed (steady-state running speed), acceleration and deceleration time of each position and the waiting time between segment could all be set. Table 6-19 are the related function codes of the 1st segment running curve.

Table 6-21 The 1st position operation curve parameters table

After setting the above parameters, the actual operation curve of the motor is shown in Figure 6-23.

• multi-segment position instruction enable

When selecting multi-segment position instruction as the instruction source, configure 1 DI port channel of the servo drive to function 20 (internal multi-segment position enable signal), and confirm the valid logic of the DI terminal.

It should be noted that only when the internal multi-segment position enable signal is OFF, can the P07 group parameters be actually modified to write into the servo drive!

Electronic gear ratio

Definition of electronic gear ratio

In the position control mode, the input position instruction (instruction unit) is to set the load displacement, and the motor position instruction (encoder unit) is to set the motor displacement, in order to establish the proportional relationship between the motor position instruction and the input position instruction, electronic gear ratio function is used. "instruction unit" refers to the minimum resolvable value input from the control device(HMI/PLC) to the servo drive. "Encoder unit" refers to the value of the input instruction processed by the electronic gear ratio.

With the function of the frequency division (electronic gear ratio <1) or multiplication (electronic gear ratio > 1) of the electronic gear ratio, the actual the motor rotation or movement displacement can be set when the input position instruction is 1 instruction unit.

It it noted that the electronic gear ratio setting range of the 2500-line incremental encoder should meet the formula (6-1), and the electronic gear ratio setting range of the 17-bit encoder should meet the formula (6-2), setting range of the electronic gear ratio of 23-bit encoder should meet the formula (6-3)

Otherwise, the servo drive will report Er.35: "Electronic gear ratio setting exceeds the limit"!

Setting steps of electronic gear ratio

lectronic gear ratio switch setting

When the function code P00-16 is 0, the electronic gear ratio switching function could be used. You could switch between electronic gear 1 and electronic gear 2 as needed. There is only one set of gear ratios at any time. Related function codes are shown in the table below.

Table 6-20 Electronic gear ratio function code

To use electronic gear ratio 2, it is necessary to configure any DI port as function 09 (GEAR-SEL electronic gear switch 1), and determine the valid logic of the DI terminal.

Table 6-21 Switching conditions of electronic gear ratio group

Table 6-22 Application of electronic gear ratio

When the function code P00-16 is not 0, the electronic gear ratio  is invalid.

Position instruction filtering

Position instruction filtering is to filter the position instruction (encoder unit) after the electronic gear ratio frequency division or frequency multiplication, including first-order low-pass filtering and average filtering operation.

In the following situations, position instruction filtering should be added.

1. The position instruction output by host computer has not been processed with acceleration or deceleration;
2. The pulse instruction frequency is low;
3. When the electronic gear ratio is 10 times or more.

Reasonable setting of the position loop filter time constant can operate the motor more smoothly, so that the motor speed will not overshoot before reaching the stable point. This setting has no effect on the number of instruction pulses. The filter time is not as long as possible. If the filter time is longer, the delay time will be longer too, and the response time will be correspondingly longer. It is an illustration of several kinds of position filtering.

Table 6-25 Position instruction filter function code

Clearance of position deviation

Position deviation clearance means that the drive could zero the deviation register in position mode. The user can realize the function of clearing the position deviation through the DI terminal;

Position deviation = (position instruction-position feedback) (encoder unit)

Position-related DO output function

The feedback value of position instruction is compared with different thresholds, and output DO signal for host computer use.

Positioning completion/positioning approach output

the positioning completion function means that when the position deviation meets the value set by P05-12, it could be considered that the positioning is complete in position control mode. At this time, servo drive could output the positioning completion signal, and the host computer could confirm the completion of the positioning of servo drive after receiving the signal.

When using the positioning completion or approach function, you could also set positioning completion, positioning approach conditions, window and hold time. The principle of window filter time is shown in Figure 6-27.

To use the positioning completion/positioning approach function, a DO terminal of the servo drive should be assigned to the function 134 (P-COIN, positioning completion)/ 135 (P-NEAR, positioning approach). The related code parameters and DO function codes are shown as Table 6-24.

Table 6-26 Function code parameters of positioning completion

Table 6-27 Description of DO rotation detection function code

VD2-0xxSA1H collector pulse signal DO Function and VD2L pulse signal DO output function

(1) VD2-0xxSA1H collector pulse signal DO Function

The pulse signal of VD2-0xxSA1H is a collector signal output through DO, which can be connected to the high-speed pulse input of PLC without conversion through differential to collector circuit board. However, the pulse frequency division output used by VD2 series is a differential signal, which needs to pass through differential to collector circuit board to be connected to the high-speed pulse input of PLC.

(2) Pulse signal DO output function of VD2L-0xxSA1P

The pulse signal of VD2L-0xxSA1P is the collector signal output by DO, and it can be connected to the high-speed pulse input of PLC without the conversion of differential to collector circuit board.

(3) The difference of collector pulse signal DO Function of VD2-0xxSA1H and DO output function of pulse signal of VD2L-0xxSA1P

The pulse signal of VD2-0xxSA1H is the collector signal output through DO, and it is a 4 times frequency pulse signal of Phase A/B. DO signal of VD2L is a pulse+direction signal.

DO2, DO3, and DO4 respectively correspond to the pulse frequency division outputs of the Z-axis, A-axis, and B-axis of the pulse output, as shown in the following table.

Speed control mode

Speed control refers to controlling the speed of the machine through speed instructions. Given the speed instruction by digital voltage or communication, the servo drive can control the mechanical speed fast and precisely. Therefore, the speed control mode is mainly used to control the rotation speed such as analog CNC engraving and milling machine. Figure 6-28 is the speed control block diagram.

Speed instruction input setting

In speed control mode, VD2A and VD2B servo drives have two instruction source: internal speed instruction and analog speed instruction. VD2F drive only supports internal speed instruction. Speed instruction source is set by function code P01-01.

Table 6-26 Speed instruction source parameter

Speed instruction source is internal speed instruction (P01-01=0)

Speed instruction comes from internal instruction, and the internal speed instruction is given by a number. The VD2 series servo drive has internal multi-segment speed running function. There are 8 segments speed instructions stored in servo drive, and the speed of each segment could be set individually. The servo drive uses the 1st segment internal speed by default. To use the 2nd to 8th segment internal speed, the corresponding number of DI terminals must be configured as functions 13, 14, and 15. The detailed parameters and function codes are shown as belo

Table 6-27 Internal speed instruction parameters

Table 6-28 DI multi-speed function code description

The multi-speed segment number is a 3-bit binary number, and the DI terminal logic is level valid. When the input level is valid, the segment selection bit value is 1, otherwise it is 0. The corresponding relationship between INSPD1 to 3 and segment numbers is shown as below.

Table 6-29 Correspondence between INSPD bits and segment numbers

Speed instruction source is internal speed instruction (P01-01=1)

The servo drive processes the analog voltage signal output by the host computer or other equipment as a speed instruction. VD2A and VD2B series servo drives have 2 analog input channels: AI_1 and AI_2. AI_1 is analog speed input, and AI_2 is analog speed limit.

Taking AI_1 as an example, the method of setting the speed instruction of analog voltage is illustrated as below.

Explanation of related terms:

• Zero drift: When analog input voltage is 0, the servo drive sample voltage value relative to the value of GND.
• Bias: After zero drift correction, the corresponding analog input voltage when the sample voltage is 0.
• Dead zone: It is the corresponding analog input voltage interval when the sample voltage is 0.

Table 6-30 AI_1 parameters

Acceleration and deceleration time setting

The acceleration and deceleration time setting can achieve the expectation of controlling acceleration by converting the speed instruction with higher acceleration into the speed instruction with gentle acceleration.

In the speed control mode, excessive acceleration of the speed instruction will cause the motor to jump or vibrate. Therefore, a suitable acceleration and deceleration time can realize the smooth speed change of the motor and avoid the occurrence of mechanical damage caused by the above situation.

Table 6-31 Acceleration and deceleration time parameters

Speed instruction limit

In speed mode, the servo drive could limit the size of the speed instruction. The sources of speed instruction limit include:

1. P01-10: Set the maximum speed limit value
2. P01-12: Set forward speed limit value
3. P01-13: Set reverse speed limit value
4. The maximum speed of the motor: determined by motor model

The actual motor speed limit interval satisfies the following relationship:

The amplitude of forward speed instruction ≤ min (Maximum motor speed, P01-10, P01-12)

The amplitude of negative speed command ≤ min (Maximum motor speed, P01-10, P01-13)

Table 6-32 Rotation speed related function codes

Zero-speed clamp function

The zero speed clamp function refers to the speed control mode, when the zero speed clamp signal (ZCLAMP) is valid, and the absolute value of the speed instruction is lower than the zero speed clamp speed threshold (P01-22), the servo motor is at In locked state, the servo drive is in position lock mode at this time, and the speed instruction is invalid.

If the speed instruction amplitude is greater than zero-speed clamp speed threshold, the servo motor exits the locked state and continues to run according to the current input speed instruction.

Table 6-33 Zero-speed clamp related parameters

Speed-related DO output function

The feedback value of the position instruction is compared with different thresholds, and could output DO signal for host computer use.

Rotation detection signal

After the speed instruction is filtered, the absolute value of the actual speed absolute value of the servo motor reaches P05-16 (rotation detection speed threshold), it could be considered that the motor is rotating. At this time, the servo drive outputs a rotation detection signal (TGON), which can be used to confirm that the motor has rotated. On the contrary, when the absolute value of the actual rotation speed of the servo motor is less than P05-16, it is considered that the motor is not rotating.

To use the motor rotation detection signal output function, a DO terminal of the servo drive should be assigned to function 132 (T-COIN, rotation detection). The function code parameters and related DO function codes are shown in Table 6-34 and Table 6-35.

Table 6-34 Rotation detection speed threshold parameters

Table 6-35 DO rotation detection function code

Zero-speed signal

If the absolute value of the actual speed of servo motor is less than a certain threshold P05-19, it is considered that servo motor stops rotating (close to a standstill), and the servo drive outputs a zero speed signal (ZSP) at this time. On the contrary, if the absolute value of the actual speed of the servo motor is not less than this value, it is considered that the motor is not at a standstill and the zero-speed signal is invalid.

To use the motor zero-speed signal output function, a DO terminal of servo drive should be assigned to function 133 (ZSP, zero-speed signal). The function code parameters and related DO function codes are shown in Table 6-36 and Table 6-37.

Table 6-36 Zero-speed output signal threshold parameter

Table 6-37 DO zero-speed signal function code

Speed consistent signal

When the absolute value of the deviation between the actual speed of the servo motor after filtering and the speed instruction meets a certain threshold P05-17, it is considered that the actual speed of the motor has reached the set value, and the servo drive outputs a speed coincidence signal (V-COIN) at this time. Conversely, if the absolute value of the deviation between the actual speed of the servo motor and the set speed instruction after filtering exceeds the threshold, the speed consistent signal is invalid.

To use the motor speed consistent function, a DO terminal of the servo drive should be assigned to function 136 (V-COIN, consistent speed). The function code parameters and related DO function codes are shown in Table 6-38 and Table 6-39.

Table 6-38 Speed consistent signal threshold parameters

Table 6-39 DO speed consistent function code

Speed approach signal

After filtering, the absolute value of the actual speed of the servo motor exceeds a certain threshold [P05-17], and it is considered that the actual speed of the servo motor has reached the expected value. At this time, the servo drive can output a speed close signal (V-NEAR) through the DO terminal. Conversely, if the absolute value of the actual speed of the servo motor after filtering is not greater than this value, the speed approach signal is invalid.

To use the motor speed approach function, a DO terminal of the servo drive should be assigned to function 137 (V-NEAR, speed approach). The function code parameters and related DO function codes are shown in Table 6-40 and Table 6-41.

Table 6-40 Speed approaching signal threshold parameters

Table 6-41 DO speed approach function code

Torque control mode

The current of the servo motor has a linear relationship with the torque. Therefore, the control of the current can realize the control of the torque. Torque control refers to controlling the output torque of the motor through torque instructions. Torque instruction could be given by internal instruction and analog voltage.

Torque instruction input setting

In torque instruction, VD2A and VD2B servo drives have two instruction source: internal torque instruction and analog torque instruction. VD2F drive only has internal torque instruction. The torque instruction source is set by the function code P01-07.

Table 6-42 Torque instruction source parameter

Torque instruction source is internal torque instruction (P01-07=0)

Torque instruction source is from inside, the value is set by function code P01-08.

Table 6-43 Torque instruction keyboard set value

Torque instruction source is AI_1 analog input (P01-07=1)

The servo drive processes the analog voltage signal output by host computer or other equipment as torque instruction. VD2A and VD2B series servo drives have 2 analog input channels: AI_1 and AI_2. AI_1 is analog torque input, and AI_2 is analog torque limit.

Taking AI_1 as an example, the method of setting torque instruction of analog voltage is as below.

Explanation of related terms:

• Zero drift: When analog input voltage is 0, the servo drive sample voltage value relative to the value of GND.
• Bias: After zero drift correction, the corresponding analog input voltage when the sample voltage is 0.
• Dead zone: It is the corresponding analog input voltage interval when the sample voltage is 0.

Table 6-44 AI_1 parameters

Torque instruction filtering

In torque mode, the servo drive could realize low-pass filtering of torque instruction, making the instruction smoother and reducing the vibration of servo motor. The first-order filtering is shown in Figure 6-43.

Table 6-45 Torque filtering time constant parameter details

Torque instruction limit

When the absolute value of torque instruction input by host computer is greater than the absolute value of torque instruction limit, the drive's actual torque instruction is limited and equal to the limit value of torque instruction. Otherwise, it is equal to the torque instruction value input by host computer.

At any time, there is only one valid torque limit value. And the positive and negative torque limit values do not exceed the maximum torque of drive and motor and ±300.0% of the rated torque.

Set torque limit source

You need to set the torque limit source by function code P01-14. After the setting, the drive torque instruction will be limited within the torque limit value. When the torque limit value is reached, the motor will operate with the torque limit value as the torque instruction. The torque limit value should be set according to the load operation requirements. If the setting is too small, the motor's acceleration and deceleration capacity may be weakened. During constant torque operation, the actual motor speed cannot reach the required value.

• Torque limit source is internal torque instruction (P01-14=0)

Torque limit source is from inside, you need to set torque limit, and the value is set by function code P01-15 and P01-16.

Table 6-46 Torque limit parameter details

• Torque limit source is external (P01-14=1)

Torque limit source is from external analog channel. The limit value is determined by the torque value corresponding to external AI_2 terminal.

Set torque limit DO signal output

When torque instruction reaches the torque limit value, the drive outputs a torque limit signal (T-LIMIT) for the host computer use. At this time, one DO terminal of the drive should be assigned to function 139 (T-LIMIT, in torque limit) , and confirm that the terminal logic is valid.

Table 6-47 DO torque limit function codes

Speed limit in torque mode

In torque mode, if the given torque instruction is too large to exceed the load torque of the mechanical side. This would cause the servo motor to continuously accelerate and overspeed. In order to protect the machinery, the speed of the motor must be limited.

In torque mode, the actual motor speed would be in the limited speed. After the speed limit is reached, the motor runs at a constant speed at the speed limit. The running curves are shown as Figure 6-45 and Figure 6-46.

Table 6-48 Speed limit parameters in torque mode

✎Note: Function codes P01-17 and P01-18 are only effective in limiting motor speed under the torque mode. The speed limit value is set according to load requirements. To set speed limit in speed mode or position mode, please refer to 6.3.3 Speed instruction limit.

Torque-related DO output functions

The feedback value of torque instruction is compared with different thresholds, and could output the DO signal for the host computer use. The DO terminal of the servo drive is assigned to different functions and determine the logic to be valid.

Torque arrival

The torque arrival function is used to determine whether the actual torque instruction reaches the set interval. When the actual torque instruction reaches the torque instruction threshold, the servo drive outputs a torque arrival signal (T-COIN) for the host computer use.

To use the torque arrival function, a DO terminal of the servo drive should be assigned to function 138 (T-COIN, torque arrival). The function code parameters and related DO function codes are shown in Table 6-49 and Table 6-50.

Table 6-49 Torque arrival parameters

Table 6-50 DO Torque Arrival Function Code

Mixed control mode

Mixed control mode means that when the servo enable is ON and the status of the servo drive is "run", the mode of the servo drive could be switched between different modes. The VD2 series servo drives have the following 3 mixed control modes:

• Position mode⇔ Speed mode
• Position mode ⇔Torque mode
• Speed mode ⇔Torque mode

Set the function code P00-01 through the software of Wecon “SCTool” or servo drive panel, and the servo drive will run in mixed mode.

Table 6-51 Mixed control mode parameters

Please set the servo drive parameters in different control modes according to the mechanical structure and indicators. The setting method refer to “Parameters”. When function code P00-01=4/5/6 (that is, in mixed mode), a DI terminal of the servo drive needs to be assigned to function 17 (MixModeSel, mixed mode selection), and the DI terminal logic is determined to be valid.

Table 6-52 Description of DI function codes in control mode

Absolute system

Overview

Absolute encoder could detect the position of the servo motor within one turn, and could count the number of turns of the motor. This series of servo drives are equipped with a maximum of 23-bit encoders and could memorize 16-bit multi-turn data, and position, speed, torque control modes could be used. Especially in position control, the absolute value encoder does not need to count, could achieve direct internal high-speed reading and external output, and could significantly reduce the subsequent calculation tasks of the receiving device controller. When the drive is powered off, the encoder uses battery backup data. After power on, the drive uses the encoder's absolute position to calculate the absolute mechanical position, eliminating the need for repeated mechanical origin reset operations.

The absolute value encoder is determined by the mechanical position of the photoelectric code disc, and is not affected by power failure or interference. Each position of the absolute encoder determined by the mechanical position is unique, and no external sensor is required to assist in memorizing position.

Single-turn absolute value system

The single-turn absolute value system is applicable for the equipment load stroke within the single-turn range of the encoder. At this time, the absolute encoder is only as a single-turn system function and does not need to be connected to the battery. The types and information of encoders adapted to VD2 series servo drives are shown as below.

Table 6-53 Single-turn absolute encoder information

The relationship between encoder feedback position and rotating load position is shown in the figure below. (take a 17-bit encoder as an example).

Multi-turn absolute value system

The encoder adapted to the multi-turn absolute value system is equipped with 16-bit RAM memory. Compared with the single-turn absolute value, it can additionally memorize the number of turns of the 16-bit encoder. The multi-turn absolute encoder is equipped with a battery (the battery is installed on the encoder cable with a battery unit), which can achieve direct internal high-speed readings and external output without the need for external sensors to assist memory positions. The types and information of encoders adapted to VD2 series servo drives are shown as below.

Table 6-54 Multi-turn absolute encoder information

The relationship between encoder feedback position and rotating load multi-turn is shown in the figure below (take a 23-bit encoder as an example).

Related functions and parameters

Encoder feedback data

The feedback data of the absolute value encoder can be divided into the position within 1 turn of the absolute value encoder and the number of rotations of the absolute value encoder. The related information of the two feedback data is shown in the table below.

Table 6-55 Encoder feedback data

Shield multi-turn absolute encoder battery fault

The VD2 series absolute value servo drive provides shielded multi-turn absolute encoder battery fault function to shield under voltage and low-voltage fault. You could set by setting the function code P00-30.

This function is permitted when a multi-turn absolute encoder motor is used as a single-turn absolute and when it is confirmed that no mechanical failure will occur.

A93 warning solution

Check the encoder communication wire and its placement, reduce the abnormal frequency, and eliminate A93. In this way, the A93 warning problem can be completely solved, and the operation of the motor will not be affected after the A93 warning is released.
Increase the threshold for encoder read-write check exceptions is only suitable as a temporary solution. Eliminate A93 warning by increasing exception threshold. The disadvantage is that the motor may run in an unstable state.

Absolute value system encoder battery box use precautions.

Cautions

Er.40 (Encoder battery failure) will occur when the battery is turned on for the first time, and the function code P10-03 must be set to 1 to clear the encoder fault to operate the absolute value system again.

When it is detected that the battery voltage is less than 3.1V, A-92 (Encoder battery low voltage warning) will occur. Please replace the battery in time.

Replace the battery

Please replace the battery while keeping the servo drive and motor well connected and the power on.

The specific replacement method is as follows:

• Step1 Push open the buckles on both ends of the outer cover of the battery compartment and open the outer cover.
• Step2 Remove the old battery.
• Step3 Embed the new battery, and the battery plug wire according to the anti-dull port on the battery box for placement.
• Step4 Close the outer cover of the battery box, please be careful not to pinch the connector wiring when closing.

When the servo drive is powered off, if the battery is replaced and powered on again, Er.40 (encoder battery failure) will occur, and the multi-turn data will change suddenly. Please set the function code P10-03 or P10-06 to 1 to clear the encoder fault alarms and perform the origin return function operation again.

Table 6-56 Absolute encoder reset enable parameter

Battery selection

Table 6-57 Absolute value encoder battery information

✎Note: 

If the battery is replaced when the servo drive is powered off, the encoder data will be lost.

When the servo drive is powered off, please ensure that the maximum speed of motor does not exceed 3000 rpm to ensure that the encoder position information is accurately recorded. Please store the storage device according to the specified ambient temperature, and ensure that the encoder battery has reliable contact and sufficient power, otherwise the encoder position information may be lost.

Correct placement of batteries +, - direction

1. Do not disassemble the battery or put the battery into the fire! If the battery is put into the fire or heated, there is a risk of explosion!
2. This battery cannot be charged.
3. If the battery is left inside the machine after a long period of use or the battery is no longer usable, liquid may leak out, etc. Please replace it as soon as possible! (Recommended to replace every 2 years, you can contact the manufacturer's technical staff for replacement)
4. Do not allow the battery to short-circuit or peel the battery skin! Otherwise, there may be a one-time outflow of high current, making the battery's power weakened, or even rupture.
5. After the replacement of the battery, please dispose of it according to local laws and regulations.

Other functions

VDI

VDI (Virtual Digital Signal Input Port) is similar to hardware DI terminal. The DI function could also be assigned for use.

Take the VDI_1 terminal assignment forward drive prohibition (03-POT) as an example, and the use steps of VDI are as the figure below.

Table 6-57 Virtual VDI parameters

Port filtering time

VD2A and VD2B servo drives have 8 hardware DI terminals (DI_1 to DI_8) , and VD2F servo drive has 4 hardware DI terminals (DI_1 to DI_4) . All the DI terminals are normal terminals.

Setting value	DI channel logic selection	Illustration
0	Active high level
1	Active low level

Table 6-58 DI terminal channel logic selection

VDO

In addition to being an internal hardware output port, DO terminal is also used as a communication VDO. The communication control DO function could help you to achieve communication control DO output on the servo drive.

Take the DO_2 terminal as communication VDO, and the use steps of VDI are as the figure below.

Table 6-59 Communication control DO function parameters

Table 6-60 VDO function number

✎Note: You are advised to configure function codes for DO terminals in sequence to avoid errors during DO signal observation

If multiple DO terminals are configured with the same non-128 DI function, servo drive will occur an error “A-90” (DO port configuration is duplicate).

Motor overload protection

VD2 Series absolute encoder (VD2SA) servo drive provides motor overload protection to prevent motor burning due to high temperature. By setting function code P10-04 to modify motor overload alarm (A-82) and motor overload protection fault time (Er.34). The default value of P10-04 is 100%.

In the following cases, it could be modified according to the actual heat generation of the motor

1. The motor works in a place with high ambient temperature
2. The motor runs in cycle circulates, and the single running cycle is short and the acceleration and deceleration is frequent.

In the case of confirming that the motor will not burn out, it is also possible to shield the overload protection fault detection function (P10-04 set to 0).