The LP6 series is rated for 6W maximum output. The Run Current is preset at the factory, and can range between 2mA and 5mA. The Run Voltage is determined by dividing the maximum output power by the Run Current.
For example if a Run Current of 3mA is specified (by the customer), the Run Voltage will be (6W) / (3mA) = 2000V
Once the Run Current is set, it cannot be changed - i.e. it is not "adjustable" by the customer.