4. Operation
4.1 Trial Operation
Make sure that all wiring has been completed prior to trial operation.
Perform the following three types of trial operation in order. Instructions are given for speed control mode (standard setting) and position control mode. Unless otherwise specified, the standard parameters for speed control mode (factory settings) are used.
4.1.1 Trial Operation for Servomotor Without Load
In this section, confirm the cable connections of the main circuit power supply, servomotor and encoder. Incorrect wiring is generally the reason why servomotors fail to operate properly during the trial operation.
Confirm the wiring, and then conduct the trial operation for servomotor without load according to the following steps.
JOG Mode Operation (Fn002)
Note:
The servomotor’s rotation direction depends on the setting of parameter Pn001.0(Direction Selection).
The example above describes operation with Pn001.0 in the factory setting.
The servomotor can be operated using only the panel operator without reference from the host controller.
Please note that the Forward Run Prohibited (P-OT) and Reverse Run Prohibited (N-OT) signals are invalid during JOG mode operation.
4.1.2 Trial Operation for Servomotor without Load from Host Reference
NOTE: this function is available for ProNet-□□□MG servo drives only.
Check that the servomotor move reference or I/O signals are correctly set from the host controller to the servo drive.
Also check the wiring and polarity between the host controller and servo drive, and the servo drive operation settings are correct. This is the final check before connecting the servomotor to the machine.
(1)Servo ON Command from the Host
The following circuits are required: External input signal circuit or equivalent.
(2)Operating Procedure in Speed Control Mode (Pn005=H.□□0□)
The following circuit is required: External input signal circuit or equivalent.
■When Position Control is configured at the Host
When the servo drive conducts speed control and position control is conducted at the host controller, perform the operation below,following the operation in Operation Procedure in Speed Control Mode (Pn005=H.□□0□).
(3)Operating Procedure in Position Control Mode (Pn005=H.□□1□)
The following circuit is required: External input signal circuit or equivalent.
4.1.3 Trial Operation with the Servomotor Connected to the Machine
Follow the procedure below to perform the trial operation.
4.1.4 Trial Operation for Servomotor with Brakes
Holding brake operation of the servomotor can be controlled with the brake interlock output (/BK) signal of the servo drive.
When checking the brake operation,take advance measures to prevent vibration due to gravity acting on the machine or external forces. Check the servomotor operation and holding brake operation with the servomotor separated from the machine.If both operations are correct, connect the servomotor to the machine and perform trial operation.
Refer to 4.3.4 Setting for Holding Brakes for wiring on a servomotor with brakes and parameter settings.
4.1.5 Position Control by Host Controller
As described above, be sure to separate the servomotor and machine before performing trial operation of the servomotor without a load. Refer to the following table, and check the servomotor operation and specifications in advance.
4.2 Control Mode Selection
The control modes supported by the ProNet series servo drives are described below.
4.3 Setting Common Basic Functions
4.3.1 Setting the Servo ON Signal
This sets the servo ON signal (/S-ON) that determines whether the servomotor power is ON or OFF.
(1)Servo ON signal(/S-ON)
(2) Enabling/Disabling the Servo ON Signal
A parameter can be always used to set the servo ON condition. This eliminates the need to wire /S-ON, but care must be taken because the servo drive can operate as soon as the power is turned ON.
4.3.2 Switching the Servomotor Rotation Direction
The rotation direction of the servomotor can be switched without changing the reference pulse to the servo drive or the reference voltage polarity.
This causes the rotation the servo motor shaft is rotating to change. The output signal polarity, such as the encoder pulse output and the analog monitor signal from the servo drive do not change.
The standard setting for “forward rotation” is counterclockwise as viewed from the servomotor load end.
4.3.3 Setting the Overtravel Limit Function
The overtravel limit function forces movable machine parts to stop if they exceed the allowable range of motion and turn ON a limit switch.
(1)Connecting the overtravel signal
To use the overtravel function, connect the following overtravel limit switch to the corresponding pin number of servo drive CN1 connector correctly.
(2)Enabling/Disabling the Overtravel Signal
A parameter can be set to disable the overtravel signal. If the parameter is set, there is no need to wire the overtravel input signal.
(3) Selecting the Servomotor Stop Method
This is used to set the stop method when an overtravel(P-OT,N-OT)signal is input while theservomotor is operating
·Dynamic brake is an emergency stop function, and one of the general methods to cause a servomotor sudden stop.
·Dynamic brake suddenly stops a servomotor by shorting its electrical circuit.
·If the servomotor is frequently started and stopped by turning the power ON/OFF or using the servo ON signal(/S-ON), the DB circuit will also be repeatedly operated, degrading the servo drive’s internal elements.
·Use the speed input reference and position reference to control the starting and the stopping of the servomotor.
(4)Setting the Stop Torque for Overtravel
4.3.4 Setting for Holding Brakes
The holding brake is used when the servo drive controls a vertical axis.
A servomotor with the brake option helps prevent movable parts from shifting due to gravity when power is removed from the servo drive.
(Refer to 4.1.4 Trial Operation for Servomotor with Brakes.)
1. The servomotor with the built in brake, is a de-energization brake. It is used to hold the servomotor and cannot be used as a braking purposes. Use the holding brake only to hold a stopped servomotor.
2. When operating using only a speed loop, turn OFF the servo and set the input reference to 0V when the brake is applied.
3. When forming a position loop, do not use a mechanical brake while the servomotor is stopped because the servomotor enters servolock status.
(1) Wiring Example
Use the servo drive sequence output signal /BK and the brake power supply to form a brake ON/OFF circuit.
The following diagram shows a standard wiring example
(2) Brake interlock output
(3) Allocating Brake Interlock Output (/BK)
Brake interlock output (/BK) is not used with the factory setting.The output signal must be allocated.
Parameter Pn511 description as following:
(4) Setting the Brake ON/OFF Timing after the Servomotor Stops
With the factory setting, the /BK signal is output at the same time as the servo is turned OFF. The servo OFF timing can be changed with a parameter.
(5) Setting the Brake ON/OFF Timing When Servomotor Running
The following parameters can be used to change the /BK signal output conditions when a stop reference is output during servomotor operation due to the servo OFF or an alarm occuring.
4.3.5 Instantaneous Power Loss Settings
Determines whether to continue operation or turn the servo OFF when the power supply voltage to the servo drive main circuit is instantaneously interrupted.
4.4 Absolute Encoders
The absolute position can be read by the MODBUS protocol. In the actual control, the MODBUS protocol can read the initial position when the servomotor is stopped (S-OFF), then the real-time position during the servomotor is running can be found from the number of PG divided output pulses.
4.4.1 Selecting an Absolute Encoder
An absolute encoder can also be used as an incremental encoder
4.4.2 Handling Battery
In order for the absolute encoder to retain position data when the power is turned OFF, the data must be backedup by a battery.
Please purchase the special cable and battery case mabe by Estun if an absolute encoder is used.
Install the battary to the encoder cable:
A.Open the shell of the battery case.
B.Install the battery according to the following diagram.
C.Cover the shell of the battery case
4.4.3 Replacing Battery
The servo drive will generate an absolute encoder battery alarm(A.48) when the battery voltage drops below about 3.1V.
Battery Replacement Procedure
1. Replace the battery with only the servo drive control power supply turned ON.
2. After replacing the battery, using the panel operator with utility function Fn011 to cancel the absolute encoder battery alarm(A.48).
3. Turn ON the servo drive power back again. If it operates without any problems, the batteryreplacement has been completed.
Note:
·The servo drive will generate an absolute encoder battery alarm(A.48) when the battery voltage drops below about 3.1V.
·If an absolute encoder battery alarm(A.47) occurred, it means the battery voltage drops below about 2.5V,and the multiturn data is lost.Please reset the absolute encoder after changing the battery.
4.4.4 Absolute Encoder Setup(Fn010, Fn011)
Setting up the absolute encoder in the following cases.
·When starting the machine for the first time,set Pn002.2 to 0.
·When an encoder error alarm (A.45～A.48, A.51) is generated.
Use the panel operator in the servo drive for setup.
Note:
1. Encoder setup operation is only possible when the servo is OFF.
2. If the absolute encoder alarms(A.45～A.48, A.51 ) are displayed, cancel the alarm by using the same method as the setup. They cannot be cancelled with the servo drive alarm reset input signal(/ALM-RST).
3. Any other alarms that monitor the inside of the encoder should be cancelled by turning OFF the power.
4.5 Operating Using Speed Control with Analog Reference
NOTE: this function is available for ProNet-□□□MG servo drives only.
4.5.1 Setting Parameters
4.5.2 Setting Input Signals
(1) Speed Reference Input
Input the speed reference to the servo drive using the analog voltage reference to control the servomotor speed in proportion to the input voltage.
(2) Proportional Control Reference (/P-CON)
4.5.3 Adjusting Reference Offset
When using the speed control, the servomotor may rotate slowly even if 0V is specified as the analog voltage reference.
This happens if the host controller or external circuit has a slight offset (in the unit of mV) in the reference voltage.
Adjustments can be done manually or automatically by using the panel operator. Refer to 5.2 Operation in Utility Function Mode.
The servo drive automatically adjusts the offset when the host controller or external circuit has the offset in the reference voltage.
After completion of the automatic adjustment, the amount of offset is stored in the servo drive. The amount of offset can be checked in the speed reference offset manual adjustment mode (Fn004). Refer to 4.5.3 (2) Manual Adjustment of the Speed Reference Offset.
(1) Automatic Adjustment of the Speed Reference Offset
The automatic adjustment of reference offset (Fn003) cannot be used when a position loop has been formed with a host controller and the error pulse is changed to zero at the servomotor stop due to servolock. Use the speed reference offset manual adjustment (Fn004) described in the next section for a position loop.
The zero-clamp speed control function can be used to force the servomotor to stop while the zero speed reference is given. Refer to4.5.7 Using the Zero Clamp Function.
Note:The speed reference offset must be automatically adjusted with the servo OFF.
Adjust the speed reference offset automatically in the following procedure.
1.Turn OFF the servo drive and input the 0V reference voltage from the host controller or external circuit
2.Press the MODE key to select the utility function mode.
3.Press the INC or DEC key to select parameter Fn003.
4.Press the ENTER key to enter into the speed reference offset automatic adjustment mode.
5.Press the MODE key for more than one second, the reference offset will be automatically adjusted.
7.Press ENTER key to return to the Fn003 display of the utility function mode.
8.Thus, the speed reference offset automatic adjustment is completed.
(2) Manual Adjustment of the Speed Reference Offset
Use the speed reference offset manual adjustment (Fn004) in the following situations:
·If a loop is formed with the host controller and the postion error pulse is set to be zero when servolock is stopped.
·To deliberately set the offset to some value
·To check the offset data set in the speed reference offset automatic adjustment mode.
This function operates in the same way as the reference offset automatic adjustment mode (Fn003), except that the amount of offset is directly input during the adjustment.
The offset setting range and setting unit are as follows:
Adjust the speed reference offset manually in the following procedure.
1.Press the MODE key to select the utility function mode.
2. Press the INC or DEC key to select parameter Fn004.
3. Press the ENTER key to enter into the speed reference offset manual adjustment mode.
4. Turn ON the servo ON (/S-ON) signal. The display will be shown as below.
5. Press the ENTER key for one second to display the speed reference offset amount.
6. Press the INC or DEC key to adjust the amount of offset.
7. Press the ENTER key for one second to return to the display in step 4.
8. Press the ENTER key to return to the Fn004 display of the utility function mode.
9. Thus, the speed reference offset manual adjustment is completed.
4.5.4 Soft Start
The soft start function converts the stepwise speed reference inside the servo drive to a consistent rate of acceleration and deceleration.
Pn310 can be used to select the soft start form:
0: Slope; 1: S curve; 2: 1 st -order filter; 3: 2nd -order filter
4.5.5 Speed Reference Filter Time Constant
4.5.6 S-curve Risetime
4.5.7 Using the Zero Clamp Function
(1) Zero Clamp Function
The zero clamp function is used for systems where the host controller does not form a position loop for the speed reference input. When the zero clamp signal (/P-CON) is ON, a position loop is formed inside the servo drive as soon as the input voltage of the speed reference (V-REF) drops below the servomotor zero clamp speed. The servomotor ignores the speed reference and quickly stops and locks the servomotor. The servomotor is clamped within ±1 pulse when the zero clamp function is turned ON, and will still return to the zero clamp position even if it is forcibly rotated by an external force.
(2) Parameter Setting
(3) Input Signal Setting
4.5.8 Encoder Signal Output
Encoder feedback pulses processed inside the servo drive can be output externally.
If the servomotor is not equipped with an absolute encoder, the servomotor needs two full rotations before using the servo drive's Phase-C pulse output as the zero point reference.
Dividing:Dividing means that the divider converts data into the pulse density(Pn200) based on the pulse data of the encoder installed on the servomotor, and outputs it. The setting unit isnumber of pulses/revolution.
Pulse Dividing Ratio Setting
4.5.9 Speed coincidence output
The speed coincidence (/V-CMP) output signal is output when the actual servomotor speed during speed control is the same as the speed reference input. The host controller uses the signal as an interlock.
4.6 Operating Using Position Control
NOTE: this function is available for ProNet-□□□MG servo drives only.
Set the following parameters for position control using pulse trains.
A block diagram for position control is shown as below
4.6.1 Basic Setting in Position Control
(1)Setting a reference pulse sign
(2)Settingreference input filter for open collector signal
(3)Setting a Reference Pulse Form
Set the input form for the servo drive using parameter Pn004.2 according to the host controllerspecifications.
(4)Inverse PULS and SIGN reference
(5)Reference Pulse Input Signal Timing
(6)Connection Example
The pulse train output form from the host controller corresponds to the following:
• Line-driver Output
• +24V Open-collector output
• +12V/+5V Open-collector output
(a)Connection Example for Line-driver Output
Applicable line driver: SN75174 manufactured by TI or MC3487 or the equivalent.
(b)Connection Example for Open-Collector Gate Output
NPN OC GATE OUTPUT
PNP OC GATE OUTPUT
Note: When the host controller is applied by open-collector signal output,the input signal noise margin lowers.When a position error caused by the noise occurs,set the parameter Pn006.3.
4.6.2 Setting the Clear Signal
(1) Setting the Clear Signal
When the /CLR signal is set to low level, clear error counter:
·The error counter inside the servo drive is set to“0”
·Position loop operation is disabled.
(2) Setting the Clear SignalMode
In positioncontrol mode, pulses will be still presented in the servo drive when servo OFF, thus it should be cleared when servo drive is turned ON. Setting Pn004 to choose whether clearing the pulses automatically when servo OFF.
4.6.3 Setting the Electronic Gear
(1) Electronic Gear
The electronic gear enables the workpiece travel distance per input reference pulse from the host controller to be set to any value.
One reference pulse from the host controller, i.e., the minimum position data unit, is called a reference unit.
(2) Related Parameters
(3)Procedure for Setting the Electronic Gear Ratio
Use the following procedure to set the electronic gear ratio
(4)Electronic Gear Ratio Setting Examples
The following examples show electronic gear ratio settings for different load configurations.
·Reduce the fraction (both numerator and denominator) if the calculated result will not be within the setting range.
·For example, reduce the above numerators and denominators by four or other numbers to obtain the final results in step 7 and complete the settings.
(5)Electronic Gear Ratio Equation
4.6.4 Smoothing
A filter can be applied in the servo drive to a constant-frequency reference pulse.
(1)Selecting a Position Reference Filter
* After changing the parameter, turn OFF the power once and turn it ON again to enable the new setting.
(2)Filter-related Parameters
4.6.5 Low Frequency Vibration Suppression
(1) Note:
For the low rigidity load, low frequency vibration will occur continually at the front end of the load during fast acceleration or fast deceleration. The vibration may delay positioning time and affect the productive efficiency.
The function of low frequency vibration suppression is embedded in ProNet series servo drives by calculating the load position and compensating.
(2) Application:
Low frequency vibration suppression function is enabled in both speed control mode and position control mode.
Low frequency vibration suppression function is disabled or can not reach the expected effect in the following conditions.
Vibration is pricked up due to an external force.
Vibration frequency is between5.0Hz to 50.0Hz.
There is mechanical clearance at the mechanical connection part.
The time for movement is less than one vibration period.
(3) How to operate:
Measuring Vibration frequency
Write the frequency data measured(unit:0.1Hz) directly to Parameter Pn411, if the vibration frequency can be measured by an instrument (such as a laser interferometer).And it also can be measured indirectly by communication software ESView or FFT analsis function.
Related Parameters
4.6.6 Positioning Completion Output Signal
This signal indicates that servomotor movement has been completed during position control. Use the signal as an interlock to confirm that positioning has been completedat the host controller
4.6.7 Reference Pulse Inhibit Function(INHIBIT)
(1)Description
This function inhibits the servo drive from counting input pulses during position control.
The servomotor remains locked (clamped) while pulses are inhibited.
(2)Setting Parameters
(3)Setting Input Signals
4.6.8 Position Control (contact reference)
Position control under contact reference (parameter Pn005.1＝C). In this mode, servo drive can position with a single axes without a host controller.
There are 16 position control points with each being able to set move distance, running speed, constants for position reference filter time, and the stop time when positioning completed. Two speeds (1. speed moving toward distance switch “speed of looking for reference point”. 2. Speed moving away from distance switch “moving speed.”) of reference points could be set as:
Two position modes: 1. Absolute position mode 2. Relative position mode
Two running modes: 1. Circling mode 2. Non-circling mode
Two step switching method: 1. Delay step switching 2. /P-CON signal switching
Method of looking for reference points: 1. Forward direction 2. Reverse direction
￭Adjusting offset
Offset of each points has two correspondent parameters: one unit of the parameter is 【x 10000 reference pulse】and the other is 【x 1 reference pulse】. Setting range of both parameters is: (-9999----+9999), while offset value equals sum of those two values.
For example:
No.0 offset correspond to parameter Pn600【x 10000 reference pulse】 and Pn601【x 1 reference pulse】. Set Pn600 = 100, Pn601=-100.
No.0 offset value = Pn600x10000 reference pulse + Pn601x1 reference pulse
= 100x10000 reference pulse + (-100)x1 reference pulse
= 999900 reference pulse
With the same principle, we can conclude: in order to get the same results, we also can set Pn600 = 99 and Pn601 = 9900.
Thus, we can see when the two parameters are not zero; we can get same result by two ways: one is to set the two parameters both negative or both positive, or one negative the other positive.
￭Speed
Speed mentioned here refers to the steady speed during which the motor is running, which is similar to the pulse frequency given from the external pulse reference in position control.However, this speed has nothing to do with the electronic gear; it is the actual speed of the motor.
￭Position reference filter time constant
Same as position reference filter time constant Pn204 in common position control.
￭Time for change steps after desired position reached
Apply internal delay to change steps to a valid value in parameter Pn681.1.
Time for change steps outputs from positioning completed signal CON/, from Servo ON, or from the time when reference point is found till the Servo performs the program to control position of the point. Such period of time depends on step changing time required by a point number among start point in program.
When running point control program, if error counter is set as “not clear error counter when Servo OFF”, then the error counter might flood. If it does not flood, then the servo drive will probably run at the max. running speed when Servo ON again. PLEASE PAY ATTENTION TO THE SAFETY OF INSTRUMENT.
￭Looking for the reference point
Looking for the reference point is for establishing a zero physical point of the operating platform, which is used as zero point in the coordinates during point position control. And users may choose to find a reference point either in forward or reverse side.
How to find a reference point
Mount a limit switch in the forward or reverse side.Find a reference point in the forward direction after connecting to /PCL and in the reverse direction after connecting to /NCL. When the operating platform bumps into the limit the switch, the motor will first stop according to the way set by Pn004.0, and then rotate again against limit the switch. When the operating platform leaves the limit switch and the motor reaches the position of first photo encoder Phase C pulse,then position of operating platform is set to be the zero point of the coordinates.
How to find related parameters of reference point
Speed towards limit switch is called “speed of looking for reference point “, and the moving speed away from limit switch is called “ moving speed”. These two speeds could be set by the following parameters:
Usually, the set speed of the reference point (Pn685) is high, and the moving speed (Pn686) is low. Note: if moving speed is too high, precision of finding a reference point would be affected.
When looking for a reference point, /PCL and /NCL are no longer programmed to limit external current.
■Related parameter
4.6.9 Position Homing Control (Homing Function)
In position control mode, the servomotor always needs to operate at a fixed position. This position is normally regarded as the zero position. When the host controller is turned on, the zero position adjustment is required before processing. This zero position will be regarded as the reference point. ESTUN servo drives can perform this function by the homing function.
(1)Homing Mode Setting
(3)Input Signal Setting
Allocating HomingOutput Signal (/HOME)
(4)Description of Homing Operation
Please set Pn689 according to the actual operation in position control mode. When starting the homing function, the servomotor will run at the speed of Pn685 when detecting the rising edge of SHOM signal; the servomotor will run at the speed of Pn686 according to the setting of Pn689.1 when detecting the valid ORG signal.
When input ORG and the encoder C-Pulse is being detected, the servo drive will begin to calculate the number of homing offset pulses. When offset pulses is completed, the servomotor stops and outputs homing completion signal /HOME, then homing control is completed.
Pn685 (Hitting the origin signal (ORG)) is usually set at high speed, Pn686 (Leaving the origin signal ORG) is usually set at low speed.
Please be attention that if Pn686 is setting too high, the precision of mechanical zero position will be affected.
After hitting the origin signal ORG, the motor will return to find C-pulse; the figure is shown as below:
Corresponding position:
After hitting the origin signal ORG, the motor will find C-pulse directly; the figure is shown as below:
Corresponding position:
