Patent ID: 8548018

Claim:
A command apparatus for a plurality of laser power supplies in a gas laser oscillator including a plurality of discharge tubes and a plurality of electrodes corresponding to the plurality of discharge tubes, the command apparatus comprising: a command generating section generating commands for the plurality of laser power supplies; and a separating section separating the commands generated by the command generating section into a bias command, an output command, an offset command and a gain command, wherein the bias command has a certain command value, which is always commanded from the command generating section in a laser operational status, the output command is a command for controlling a laser output, the offset command corresponds to a variation amount in the characteristics of the load of each of the laser power supplies with respect to the bias command and the gain command corresponds to a variation amount in the characteristics of the load of each of the laser power supplies with respect to the output command; wherein the bias command and the output command are common to the plurality of laser power supplies, the offset command and the gain command are defined at least in accordance with the discharge tubes corresponding to the plurality of laser power supplies respectively, wherein the command apparatus further comprises a transmitting section transmitting, to each of the plurality of laser power supplies, the bias command and the output command which are common to the plurality of laser power supplies and, transmitting, in serial, the offset command and the gain command which are defined at least in accordance with the discharge tubes corresponding to the plurality of laser power supplies respectively, corresponding to each of the plurality of laser power supplies.