Want Better Records of Your Laser Processes? Consider SPC Data Acquisition
Manufacturers are adopting tools such as the LASERDYNE SPC (Statistical Process Control) Data Acquisition feature in an effort to more thoroughly document and control their laser processes. SPC Data Acquisition, a standard feature of the S94P control, records selected program and process information as a laser processing program is executing.
SPC Data Acquisition involves writing user-specified parameters, including time and date, axes positions, commanded and/or actual laser power, and laser pulse conditions, to a file on the hard disk of the LASERDYNE control.
The G80 command (1) enables the SPC Data Acquisition function and (2) specifies the information to be saved. To save data in a file of your choosing, program G80 ”FNAME”, where FNAME is any desired path and file name accessible from Windows (if no directory is specified, the file is written to C:Cnc-ShareOutput).
The system first goes to the end of that file (if it exists), then writes a blank line, the time and date, and the SPC data specified after the G80 command. Data is written to a ‘Cnc-ShareOutputProcess’ file if a file name is not specified.
In earlier versions of the LASERDYNE LPC software, data to be saved was defined by indicating $ parameters. Data for the parameters in the table below can be saved by programming G80 followed by text containing appropriate $ commands. Text in a G80 block without $ commands is also transferred to the output file. G58 messages can also include $ commands to display data in the S94P message window.
Following are some of the $ parameters associated with G80.
| $T | Time |
| $D | Date |
| $E1 | Log system errors with time and date |
| $E2 | Log system errors without time and date |
| $F | Commanded feedrate (in inch/minute or mm/minute) |
| $Vn | System variable value (n = variable number) |
| $P0 | Laser commanded power (in Watts) |
| $P1 | Actual power at the laser (in Watts) |
| $P2 | Actual power at workstation (requires optional power meter) (in Watts) |
| $Q0 | Override summary |
| $Q1 | Feedrate override (in %) |
| $Q2 | Power override (in %) |
| $M | M-function report – lists those of the M200 through M211 functions that are ON |
In more recent releases of S94P software, man-readable commands beginning with a question mark (‘?’) have been defined. The table below shows examples of these. Note that the relevance of some of the commands depends upon the type of laser included with the system.
For additional information refer to the S94P manual or contact LASERDYNE Sales at lds.sales@primapower.com.
| LAS NAME | Laser name |
| LAS_TYPE | Laser type number |
| LAS_DB_REC | Database record |
| LAS_SHUTTER_OPEN | 1 if shutter is open |
| LAS PULSE MODE | 1 if laser is in pulse mode |
| LAS_AVE_POWER | Average power |
| LAS PULSE FREQ | Pulse frequency |
| LAS PULSE WIDTH | Pulse width |
| LAS_SHOT_COUNT | Flashlamp shot count |
| LAS ACTIVE PULSE | Active pulse tool |
| LAS ACTIVE WAVE | Active wave tool |
| LAS SHUTTER OPEN | 1 if shutter is open |
| LAS PULSE MODE | 1 if laser is in pulse mode |
| LAS_DCRAIL1_VOLTS DC | Rail 1 voltage |
| LAS_DCRAIL2_VOLTS DC | Rail 2 voltage |
| LAS_LAMP1_CURRENT | Lamp 1 current |
| LAS_LAMP2_CURRENT | Lamp 2 current |
| LAS_LAMP1_VOLTS | Lamp 1 voltage |
| LAS_LAMP2_VOLTS | Lamp 2 voltage |
| LAS_HIGH_VOLTAGE | 1 if high voltage on |
| LAS LAMP1 POWER | Lamp 1 power |
| LAS LAMP2 POWER | Lamp 2 power |
| LAS_DCLINK1_VOLTS DC | Link 1 voltage |
| LAS_DCLINK2_VOLTS DC | Link 2 voltage |
| LAS_AVE_POWER | Average power |
| LAS_POWER_DENSITY | Power density |
| LAS_BEAM_DIA | Beam diameter |
| LAS_PULSE_FREQ | Pulse frequency |
| LAS PULSE WIDTH | Pulse width |
| LAS_PULSE_ENERGY | Pulse energy |
| LAS Dl WATER RES Dl | Deionized cooling water resistance |
| LAS_COOLANT_TEMP | Coolant temperature |
| LAS_SECTOR_HGT | Sector height |
| LAS_CT_POS CT | CT position |
| LAS_VSM1_POS VSM 1 | VSM1 position |
| LAS VSM2 POS VSM 2 | VSM2 position |
An example of a program segment that uses the SPC Data Acquisition features follows:
| G80 “0123.DAT” | ;save data to Cnc-ShareOutput 123.dat |
| V35=125.0 | ;set process variable V35 |
| G80P/N = 0123 ROTOR | ;information to file |
| G1G91F100 | ;define the feedrate |
| X-1 | ;move the X-axis |
| V1=X V2=Y | ;assign the actual positions of the X and Y axes to V1 and V2 |
| G80 ABS POS=$V1 $V2 | ;save the actual values of the X and Y axes positions |
| G80 Variable V35=$V35 | ;save the value of variable V35 |
| G80 Feedrate override=$Q1 | ;save the value of feedrate override as verification that it was at the correct value |
| G80 Power=?LAS_AVE_POWER | ;save the value of the average laser power |
