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Application Notes l Motor Wiring l Control Interface l FAQ

Frequently Asked Questions

 

 

How do I handle multi-axis motion?

There are two types of multi-axis motion: uncoordinated point to point moves that do not have to start and stop at the same time, and coordinated or synchronized moves that are required to start and stop simultaneously.

 

There are many methods for making moves if synchronization is not required. The most common is to use the RS-232 ASCII protocol and the RS-232 multi drop feature connecting subsequent drive via CAN. In this mode a simple string is sent to node 0 and passed to the proper node and then a response is sent back. See the ASCII Programmer’s Guide. I/O can be used in conjunction with the CVM Indexer to home and make sequential moves by setting PLC outputs to select a sequence and initiating a GO line. Alternatively, the RS-232 ASCII protocol can be used to read and write register variables in the Indexer program. See the CME 2 Indexer User Guide.

 

CANopen can be used to do both uncoordinated and coordinated moves and is a low cost solution when there are a large number of drives and I/O on a machine. CANopen, EtherCAT, and MACRO are three popular methods for synchronized coordinated moves. Synchronization is typically +/-1µs and update rates vary from system to system depending on the architecture. A cost/performance analysis should be made to determine the best solution for the application. Contact your Copley Controls distributor and see our Control Networks brochure.

 

How do I ENABLE the drive?

There are two main drive enables. One is hardware and the other is software. Some drives are equipped with an additional hardware safety circuit that must be jumpered. Please read Using CME2 and refer to the drive datasheet for connection details.

 

“Hardware” enable IN1 (Input 1) is typically configured by default as active LO enables the drive, programmed with pull-up to +5V for fail safe operation, so that a closed switch to ground or a low signal from the controller will enable the drive. The CME2 Input/Output screen can be used to program the hardware enable input.

 

“Software” enable for CME2 allowing for temporary drive software disable. The software disable will not cause the drive output stage to be disabled on power-up or after reset unless the drive is in a network mode. Use the CME2 Control Panel to software enable the drive or use the jog option to change from a network mode to jog mode allowing for network disable override.

 

When using a network the drive must first be hardware enabled and then the master must transition the state machine from pre-operational to operational mode before software enabling over the network.

 

Is C# supported?

Yes. All visual studio languages are supported. CMO CANopen and EtherCAT motion control software is managed code and incorporates VB.NET and C# examples.

 

Is C++ supported?

Yes. CML Copley Motion Libraries is C++ source code for CANopen and EtherCAT motion control. CML requires a license agreement and payment of a nominal fee. See EtherCAT and CANopen Control.

 

Can I use 64-bit Windows?

Yes. The CME2 set-up and tuning software is written in JAVA and uses the Java Virtual Machine written by Sun Micro Systems designed to work on 64-bit machines. The latest CMO Copley Motion Objects for CANopen and EtherCAT motion control are written in the .NET framework from MicroSoft for 64-bit machines.

 

How do I control motion from embedded systems?

Many applications use embedded systems and employ the RS-232 or RS-422 ASCII protocol for 10Hz to 100Hz update rates. The CANopen protocol has faster update rates - 100Hz to 1kHz. It is not possible to exceed 1kHz or the 1 mega bit data rate of CANopen. Copley provides CML (Copley Motion Libraries) for CANopen - C++ source code with libraries that can be compiled on any C++ compiler. CML uses floating point math and would need to be “lightened” to be used on non floating point embedded systems. CML is also available for EtherCAT sytems employing CoE (CAN application protocol over EtherCAT).

 

Do I need a special Ethernet card to use EtherCAT?

No additional hardware is required. The standard Ethernet port is used. If you need to connect the same PC to the network then another Ethernet card should be used. Copley provides EtherCAT for use on the 100BASE-TX Ethernet using CAT6 UTP or the preferred STP cable. EtherCat Technology Group provides documentation. Copley conforms to CoE (CAN application layer over EtherCAT) using the DS-402 CANopen device profile for drives and motion control.

 

Which CAN manufacturers are supported?

As long as you are not using Copley software, you can use any CAN interface and any CANopen master. With Copley software, however, you will need to use a Copley PCI CAN card or any of the Kvaser interface options. Some CML (Copley Motion Library) C++ source code users know how to make a header file for interfacing with other manufacturers' CAN drivers but such projects are not marketed by Copley. CiA (CAN in Automation) provides CANopen documentation.

 

How do I pass EMC testing?

Electromagnetic Compatibility (EMC) is concerned with the emissions from the drive and the susceptibility of the drive. The CE standards are used to test the drive’s EMC compliance and the datasheet, user guide, or manual will indicate good cabling, grounding, and shielding practices used to help pass system testing. The Copley PWM amplifier has controlled switching that significantly reduces the need for corrective action as compared with competing drives. The rugged military applications typically have much higher standards for emissions and susceptibility so Xenus rugged edge filters and special coatings have been developed to help pass the more stringent military testing.

 

Where is the UL file number for my Copley drive?

Go to the UL website, click on certification then enter “Copley Controls” as the company name and the first three letter of the model number as the Keyword. The UL online certifications d ictionary will contain the links to the relevant files for the Copley drive product.

 

Why do I get SDO timeout using CMO?

The CMO (Copley Motion Objects) software will send the first SDO (Service Data Object) message to initialize the drives. If the return message is not received in a reasonable amount of time CMO will display the SDO timeout message. Verify that correct network mode of operation and confirm proper node ID using CME2 software. The most common cause of this error message however is poor cabling so verify proper cabling. If using CANopen verify bit rate and confirm 120 ohms termination at both ends of the trunk by measuring 60 Ohms between CAN_H and CAN_L. See CAN Bus Cabling Guide.

 

How do I download firmware?

The CME2\tools\download firmware tool is used to load firmware. See Using CME2. The Copley drives ship with the latest released firmware. However, older drives may need new firmware loaded. The latest released firmware can also be found on the firmware download page. The CME2 properties screen will show version of firmware installed in the drive. OEM customers may have firmware loaded by the Copley distributor or in production quantities at the Copley factory. Firmware can also be loaded over the CANopen or EtherCAT network by using CML (Copley Motion C++ Library). See the “flash” example.

 

How do I load a .ccx file?

The .ccx file is a Copley Controls Axis file that contains the settings for the drive variables typically created by the design engineer during development for use in production. The CME2 File\Restore\Amplifier Data method or “Restore Amplifier Data from Disk” button can be used to load the drive .ccx file to drive working memory (RAM). Be sure to also save to FLASH by press the “Save amplifier working memory to FLASH” button. See Using CME2. If CME2 is not authorized for use in production then the CFT (Copley File Transfer) Windows tool can be used. The .ccx file can also be loaded over the CANopen or EtherCAT network from the Copley CMO or CML software using the LoadFromFile method.

 

Why is there no status LED illumination?

Plug it in and turn it on! The AC powered drives do required a +24Vdc keep alive voltage. Use the drive datasheet to verify proper connection and polarity of the DC power supply. Many of the DC powered drives have an AUX HV that can also be used with a +24Vdc keep alive but it not required for operation.

 

Why is the LED blinking green?

Now enable the drive to make it solid green. There are two speeds of blinking green: slow (twice every second) and fast (four times a second). Fast indicates a positive or negative limit is active and inhibiting motion. Slow is just a disabled drive. Please read the Using CME2.

 

Why is the status LED solid red?

Plug in the AC power cord. Actually there are several faults that are not latching by default. Under Voltage, Over Voltage, Following Error, Phase Fault, and Command Fault. Please read the Using CME2 section 9.1: Fault Configuration Parameters to see how to clear these faults.

 

Why do I get a phase fault?

When using Halls and Encoder, Copley continuously monitors the relationship between the Halls and the encoder as a redundant feedback system and when there is a disagreement between the Halls and encoder count of greater than one Hall state a phase fault will be issued.

 

Case No. 1: cabling, grounding, and shielding. The most common error is to not provide a path for the encoder shield to earth. With an ohm-meter verify 0 ohms between the shield and the earth ground. Copley provides a frame ground pin on the drive and recommends that the shield wire be connected to that pin. It is also critical that the heatplate of the drive finds a conductive path to the fame of the machine assumed to be connected to earth or provide a direct connection to earth ground. Verify that any black anodized aluminum is scratched through so that the heatplate finds a good path to the frame and earth ground. Use differential encoders (A /A B /B) with good twisted shielded cable for feedback and do not bundle the motor power wires with the feedback cable. Make sure there is a good path to earth for the motor frame.

 

Case No. 2: hot swapping. Under no circumstances should hot swapping ever be authorized. One problem with doing this is that the Hall state will change forcing a false transition to sinusoidal commutation and a subsequent phase fault. The other is that potential damage to the encoder circuits could occur.

 

Case No. 3: bad encoder. Use CME2 and verify on the Control Panel that one rev of the motor shaft should produce the correct number of counts. Use a two channel oscilloscope to measure A and /A using the add and invert option to verify a good differential signal. Check with drive disabled and then again enabled commanding 0A.

 

Case No. 4 bad Halls. Use the CME2 manual phase screen to verify that all three Hall lines change states and that one electrical cycle will produce one rotation of the dial. Lose stators will cause Hall position to shift when large torque is applied. Bad adhesives will cause Halls to fall off and dangle in place.

 

Why do I have a Voltage Limited warning

The drive will monitor the PWM pulse width to see if it hit 95% and if so it will issue a voltage limit warning. The warning is okay as long as there are no subsequent faults being generated.

 

Case No. 1: momentary voltage limit warning that does not limit the voltage for more than one or two PWM update cycles. When a PWM amplifier is adjusting the duty cycle to control the current to the winding it is possible that the PWM pulse width could hit 95% due to the characteristics of the load and tuning. In this case the warning will be intermittent and not cause any increase in following error or limiting of the systems velocity or position loops. These warnings may be ignored.

 

Case No. 2: continuous voltage limiting warning that limits the voltage for many PWM cycles. In this case the voltage to the motor is being limited and the motor may not get the voltage it needs to compensate for back emf, IR drop, and inductive compensation. The best way to determine the margin in the system is to trace the Profile Velocity, following error, Actual Current, Voltage Bus, Voltage Terminal Servo, and event status voltage limiting. If the following error is increasing beyond a reasonable amount and the voltage limit warning is constant during that time then these warnings can not be ignored. Increase the dc bus voltage, decrease top speed, or reduce acceleration if IR drop is large.

 

What if there are no Halls?

Resolver, Absolute Encoders, and DC brush motors do not require Halls because they provide absolute position for commutation. Brushless motors with incremental encoders typically have Halls. Ask the motor manufacturer to provide Halls on the motor. It is traditional in the USA to have Halls for reliability. No Halls operation has risks associated with the commutation of the brushless motor. The method for phasing with no Halls is algorithmic phasing. After power-up and enable, the motor will have to wiggle to determine the location of the magnets in the electrical cycle. Phasing will fail if the brake is on, the motor can not move, and if gravity or some external force is somehow affecting the ability to wiggle.

 

Auto-Phase failed, what do I do?

Auto Phasing should not fail if the rules are followed. The rules for Auto Phasing are outlined in Using CME2. The most common problem is the inability to remove a load. In this case use Manual Phasing to phase the motor and verify the wiring. Auto Phasing should not be performed in production. The design engineer has already configured the phasing and provided the .ccx file and a proper wiring diagram. Verify correct wiring and use manual phase screen to verify good Hall state changes, encoder counts, and UVW current. It is possible that the motor manufacture has made a color change but it is not possible that the Copley hardware circuit has changed in such a way.

 

Why do I have a following error?

Remove the mechanical obstruction and clear the fault using the CME2 Control Panel. If there is no mechanical problem then open the Error Log, clear faults, and run until error occurs again checking for other errors or warnings that may indicate the source of the problem. The most common cause of following error is caused by a current limiting.

 

Why do I have a current limited warning?

Check the motor specification to see if the continuous current is rated in Arms or Ap-p. The value on the CME2 current loop screen should be entered in Ap-p so if the motor is in Arms multiply by square root of two to get Ap-p. Do not exceed the rated current limit of the motor.

 

Case No. 1: high duty cycle. When using high peak and continues currents in a profile move be sure to check the rms of the typically profile and dwell time. The CME2 scope trace has measurement tools for determining the rms of actual current during the duty cycle. The Arms should be less than the setting for the continuous current setting. Decrease acceleration and deceleration to reduce rms current.

 

Case No. 2: phase leakage. If phase information is lost, the motor will not produce proper torque or force. When using an encoder with no Halls if there are false counts then no phase fault will be issued and proper phase will be lost. If using absolute feedback, resolver, or encoder with Halls check that the feedback is not lost. If feedback is good then check that the stator is not shifting.

 

What is the drive efficiency?

Overall drive efficiency depends on the operating conditions of voltage and current. Check the data sheet of the drive for details. Note that some vendors specify the efficiency only of the power transistor stage and do not include the quiescent current (logic and encoder supplies). Copley incorporates quiescent current for a true efficiency number. The efficiency of the output stage on Copley drives is typically 99%.

 

Where are the CE documents?

Copley drives conform to CE standards for emissions, susceptibility, and safety. On the download page of each drive family there is a declaration of conformity document listing the EN, IEC, and UL specifications. Any appropriate accessories or instructions used to pass CE, such as AC line filter, will be noted in the appropriate datasheet, user guide, or manual.

 

Where are the RoHS and ISO certificates?

Look in the right column on the Copley Home Page.