However, first I would like to distinguish between the laser receiver sensitivity and sensitivity of the control system.
For the proportional laser receiver LS-3000 no external sensitivity adjustment is provided on the control system (Via CAN theoretically possible). The resolution the laser beam is measured during initialization of the receiver is always at the highest = 0.1 mm.If the beam can not clearly be detected (e.g. mirrors), the LS-3000 reduces its sensitivity automatically until it reaches a reliable measurement. How sensitive the control system react to the measured values or a change from set point is determined only by the sensitivity setting at the controller.
Basically, you can say that the control sensitivity is a kind of combination of dead band (no valve control) and proportional range (linear increase in the valve output, depending on the value within this range). There are, in laser-matic controller as well as at the controller for the GS-508, fixed stored tables (these are presented in the respective manuals).
An example: The sensitivity value 9 in the laser-matic corresponds to a dead band of 0.9 mm and a Proportional range of 12.7 mm. The result by a measured deviation will be as follows
- e.g. 0.3 mm deviation = no control of the valves (since within the dead band)
- e.g. 1.0 mm deviation = a valve control with very low current (at voltage control valves, with a correspondingly small change in voltage to Vcc ½)
- e.g. 10 mm deviation = a valve control with a higher current (at voltage control valves, with a correspondingly high change in voltage to Vcc ½)
What the respective current or voltage is at a certain deviation is actually determined via the hydraulic calibration, were the minimum current (voltage) and maximum current (voltage) will be fixed.
Also here an example: If I set the minimum current (the cylinder make the smallest possible movement) to 0.25 Amp. and the max. current to 1 Amp. the valves controlled from 1% (0.25 A) up to 100% ( 1A), over the proportional band range of 12.7 mm (see our example above).
Same with voltage controlled valves (Danfoss).
Vcc ½ (12 V @ machines with 24V power supply or 6V @ machines with 12V power supply) means no reaction at the valves. If during the hydraulic calibration a minimum output voltage set to e.g. 12,5V (for UP)/11,5 V (for DOWN) and 18V/8V for max. output voltage the valves will be controlled within the proportional band from 1% (12,5V/11,5 V) up to 100% 18V/8V.
Maybe the attached graphic helps to make it a bit clearer.