LC-C50 Laser Controller, for Coherent Diamond G50 and G100 CO2-Lasers

The laser controller LC-C50 is designed to control the operation of the Coherent DIAMONDTM G-50/100 OEM CO2-Lasers. Typical applications include laser cutting and engraving, but also the scientific use is supported. With the LC-C50 controller AED offers a complete solution, so there is need for in-house development of a system.

Front panel of the AED LC-C50 controller.

Features of the LC-C50 controller:

Glitch free, digital pulse-width-modulation (PWM) circuit.
Complete control over the laser modulation: Frequency and duty cycle are set through the controller’s serial port, or by potentiometers at the front panel.
The laser output power at the selected frequency and duty cycle combination is displayed at the controller’s liquid crystal display (LCD). The default calibration values can be overruled by the user’s calibration data. To calibrate the laser a convenient calibration routine is present in the controller’s firmware.
Remote voltage control (RVC) mode allows modulation of the laser output by an externally applied voltage. In the remote voltage control mode, the laser is modulated at a fixed frequency by varying the duty cycle. The duty cycle circuitry assures glitch free operation when the duty cycle is continuously varied. A new value of the new duty cycle is only latched into the PWM circuit after each completed period.
Modulation of laser by (user defined) waveforms.
Light emitting diodes (LED’s) at the front panel warn the user in case of a laser malfunction.
LabVIEW(r) drivers available for control via RS-232.

(For more details, please check the tail of this page.)

  LC-C50 with Coherent DIAMONDTM G-50 in an experimental setup for ignition of solid rocket propellants, at Delft University of Technology, department of Applied Physics.  

LC-C50 Specifications:

PWM Output Frequency range 25 - 133k Hz
   Duty cycle range 0 – 100 %
Input signals Digital signals TTL -
Remote voltage control 0…5 V
Output signals Digital signals TTL -
Analog reflected       0…5 V
Serial port RS-232 (-12V/+12V signals)      
Interlock    0/+12V, < 50 mA  
Physical Properties 19”-rack, height 2E         
Weight   2 kg

For more details, download the LC-C50 user manual (402kB, pdf format).

Pricing and Availability:

For more information, or pricing and availability information, please contact us.

Theory of operation

The main components of the laser controller are shown schematically in the figure below. The controller is divided into two printed circuit boards, the main board and the front panel printed circuit board. The main board contains the core of the controller: the microprocessor (uP) and its memory (RAM, ROM and E2PROM). The E2PROM is used to store user data, even if the controller is shut off (like custom waveforms and calibration data). The microprocessor communicates with the user through the front panel by means of switches, potentiometers and a LCD.


Block diagram of the LC-50 laser controller.

The power output of the Coherent DIAMONDTM G-50/100 Laser is set by a Pulse-Width-Modulation (PWM) signal [1]. The output power increases with increasing Duty Cycle (DC) of the PWM-signal. Varying the frequency of the PWM-signal sets the properties of the laser beam. The LC-C50 controller contains a computer programmable PWM-generator with variable frequency. The laser can only be enabled when the enable safety key is in the “enable” position, and the interlock switch is closed.

Several control signals are available to check the laser status. These signals are generated by the laser as differential signals (RS-485). RS-485 receivers at the front panel convert these signals to “normal” signals available at the front panel. In case of an error situation, light emitting diodes (LED’s) light up at the front panel. As several of these signals are only active during the high period of the PWM signal, warning pulses as short as 1 us may be generated. To make these pulses visible, the extension circuit elongates these signals to 0.3 seconds.