|
Why does my AMC reset when I ask it to datum ? Q: A "Limit exceeded" error keeps coming up when I try to run my program A: When the AMC controller has fixed datum points, a limit check will be done to make sure the program data is not asking the AMC to move the machine beyond it's physical limits. There are a number of reasons why valid program data may cause a problem. a.) The AMC will not start a job when one of the axis has been jogged outside it's machine limit b.) The 'home position' or 'job start position' has been changed or set to close to an axis limit c.) Arc data is invalid and AMC is trying to move to incorrect position d.) Axis directions are inverted with respect to program positional data e.) Conversion between metric/imperial units may produce very tiny errors which may cause an error when the machine is moving close to an axis limit f.) If an axis is sitting on maximum/minimum positional limit, the AMC may think it is a micron over the limit depending on the machine configuration. This sort of error is often overcome by modifying the configured 'datum position' and 'position after datum' values. There are many causes of serial errors, most are fixed very easily and quickly and are mainly caused by slight confusion by the user a.) The serial lead integrity must be 100%, before checking anything else be sure the lead is working and plugged in correctly. See NEE Controls Ltd drawing number 70125 for information on serial lead connections (supplied in installation guide) b.) Baud rate mis-matches are the most frequent cause of serial errors c.) Check the current interface selection, the controller should be flashed with the correct default interface type to save the operator having to select the interface type after power on d.) Protocol settings should be carefully compared. These are data bits, stop bits and parity. Using parity checking greatly increases the chance of detecting transmission problems and helps prevent execution of invalid data e.) Framing errors are likely to be a mis-match between data bits or stop bits f.) Parity errors are likely to be a mis-match between the parity settings on the PC or AMC. They could also be the result of a problem detected with the serial transmissions from the PC, either an interference problem or a failing com port. g.) It is advisable to use some form of handshaking, we would recommend RTS/CTS or hardware handshaking be used. This requires a 5-wire serial lead. Handshaking prevents overrun errors h.) If all else fails, try a different com port or a different PC. In most serial communications issues, the control equipment has not been at fault. The AMC serial port is extremely robust and the AMC controllers have built in test routines the user can run to check the serial port. Please refer to your system documentation for these, or download our AMC Interface Guide from this site. "Invalid I/O block" error message. Any input or output that is to be used or activated by the user within the program data must have an I/O group definition. A group is defined within the AMC configuration file. It consists of a name, an internal reference Id, a group type definition and the physical input(s) or output(s) to be controlled by the group. Check the group definitions within the configuration file. Groups are created by pressing the space bar on the last ‘undefined’ column or group. The groups may be named for easier programming from within the GPS software, more than one input or output may be assigned to a group. See the AMC Utility Programs user guide for more information on configuring the AMC controller. "Error decoding config from flash" message reported after power up. This error is normally caused by an invalid number of axis defined within the configuration file. The firmware versions for the AMC are produced to accommodate a set number of axes depending on the control systems for which they are intended. A three axis version of firmware will not work with a configuration file containing a setup for six axis, only 1 to 3 axis may be defined. The total number of defined axis within the configuration file must be less than, or equal to the maximum number of supported axis for the version of firmware being used. It is possible the error may be due to some incompatible setting within the configuration file that is conflicting with the firmware version flashed into the AMC. It is possible that the configuration file has not been updated to provide all the information that a new firmware version is expecting to decode, or that a newly updated configuration file has been flashed with an older revision of firmware. The middle two digits for any software version number produced by NEE indicate the compatibility between the different software packages, for example: AMC Utilities v2.12.24 may be used to produce configuration files for an AMC to be flashed with a firmware version 3.12.63. However the configuration file produced with this version of the Utilities will not be compatible with a much older version of firmware such as 1.10.22 Drive fault or safety circuit error message Drive fault error messages indicate that the AMC controller has detected a fault signal from one or all of the drive units it has been configured to use. On some controllers the error message also indicates which drive is at fault, for example: X-axis drive fault A common cause is the overloading or overheating of the drive. On a D.C. servo system, there may be a connection fault between the motor and the drive. If the drive is external to the controller, check the drive power and status indicators. If these are OK then a more detailed investigation will be required. You may require a meter and some tools to check the signals coming back to the AMC from the drive unit, the signals at the drive itself and the motor connections. The connection details may be obtained from the drive manufacturer and in most cases from NEE Controls technical support. All connection details for the AMC controllers are provided in the manuals supplied with the controller at time of purchase. If the drive is internal to the AMC, there may be a genuine drive failure caused by overloading, overheating, or a connection fault to the motor. Either of these problems may have caused a fuse to blow on the drive itself or in the AMC unit. Eventual failure of the main cooling fan within the AMC, simply due to wear and tear/age, may prevent the drives from being turned on. As the fan runs off the 24V supply, seizure of the fan will likely blow the 24V fuse and prevent the drives from being turned on. Check the fan for ease of rotation and all fuses on the controller to make sure this is not the case. The controller has a finite amount of memory available for job storage. If you receive this type of error, it may be due to one of the following: a.) The memory has become fragmented, the largest available block is not sufficient to store any part of the downloaded program data. To resolve this, use the 'Mem Clear' operation from the AMC menu to delete all memory content, this function de-fragments the memory as well as deleting all program data. Battery backed settings such as tool lengths will not be lost, nor will the controller need to be re-flashed. Then try sending down your program again. b.) The program size is too large for the available AMC memory. If you are running the controller interface in program buffer mode, set the buffer to ring mode to allow data to be drip fed to the AMC as needed. This allows execution of program files of any size. Q: When I run WinAMC, why are certain machine operation buttons such as datum, run job, select job etc. greyed out? A: There are several reasons why WinAMC may not be able to take control of the AMC: a.) The AMC may be controlled from a keypad/front panel or from WinAMC. The AMC must be told which type of control it must default to, this is done within the AMC configuration utility under 'Edit - Interface Parameters - WinAMC - Keypad control'. The best option is to set the control to automatic, this way the AMC will automatically switch control to the WinAMC software when it comes on-line. b.) WinAMC has two control types which allow the operator to switch control focus manually between the WinAMC software to the AMC control panel. Make sure the operator hasn't switched control focus. c.) The WinAMC software may not be communicating with the AMC controller. The communication status is shown to the bottom right corner of the WinAMC screen, on the status bar. A yellow triangle means no communications link, a white speech bubble with some blue text showing 0's and 1's indicates a healthy communications link. d.) Certain buttons are greyed out until the datum has been pressed Q: When using GPS, I download & run a job which then needs to be modified. If I modify the symbol & download again. Why does the AMC seems to ignore the changes? A: This is because you have not 'checked' the preload/reload checkboxes in the 'Machine execute' window prior to resending the job. This overwrites the original symbol stored in the AMCs memory. Alternatively, you can select 'memory clear' from the AMC front panel.This deletes all workfiles & symbols so don't do this if you have multiple programs in memory that you wish to keep. Q: My stepper system has run well for years. I have recently greased all the mechanics so why has it now started to misposition. A: Stepper motors require some friction to stop the effect of motor "resonance". The mechanical friction has been reduced so the motors have a tendency to pole slip at certain resonant frequencies. This can be solved by reducing the programmed motor current in the relevant axis drive module. Q: I have just flashed my AMC. Why does the unit keeps resetting during power up. A: Some parameters within the .ini ( AMC configuration ) file are incorrect for that particular AMC i.e. display parameters, machine type e.t.c. Q: Why does my AMC reset when I ask it to datum. A: This could be: a) Mains supply problem. When the drives are enabled at the point of datum, the extra current demanded by the motor is sufficient to "Dip" the mains supply which causes the control to reset. Ensure good mains supply to the control. b) If you have recently reflashed the control then the .ini ( AMC configuration ) file may be incorrect e.g. servo system set to stepper or vise versa. Q: The AMC stops moving and displays 'Following Error Exceeded' There are several questions you should ask when a following error becomes a problem on the system: a.) Is it the same axis that's tripping out with a following error each time? b.) Does the error only occur above a certain terminal velocity? c.) Does the error occur during acceleration, terminal velocity or deceleration? d.) Does the following error occur beyond a definitive move length? e.) Does the error occur consistently for a given job or only happen with one type of size or shape? f.) If you run the axis slower, does this stop the error occurring? How fast are you running the job? g.) Does the axis clunk or make a rough sound during movement? h.) If no following error is reported, does the AMC report datum errors if datumed after running a job? i.) Do you think you may be exceeding the acceleration/deceleration limits of the axis itself? j.) Is the system being run in velocity (tachos and encoders fitted to the motor) or torque mode? k.) Some controllers use encoder phase detection, is this function turned on? l.) How accurately are the motors tracking during rapid speed? Our WinAMC software can be setup to display positional errors as well as actual positions, the error may then be monitored during a long axis move. Q: Are NEE's controllers CE marked ? A: NEE's boxed controllers which contain drives are CE marked, conforming to the latest European Standards. EMC compliance was achieved through the development of our own precompliance testing facilities. These facilities are being offered to companies who require EMC precompliance testing and advice on design changes for EMC. Reference your specific controller's compliance certificate to determine the level that it relates to. These certificates can be found in the installation guide. Why don't we produce PC based machine controllers ? A: We have written an article explaining our views regarding the advantages and disadvantages of PC based machine controllers CAUTION
|