Bosch Rexroth R901142360

Analog amplifier for controlling pressure valves without electrical feedback. The modular design allows for simple top hat rail mounting as is usual in control cabinets. Command value input [4] The module amplifier is controlled by means of a standard command value signal 0 to +10 V. By means of the zero point potentiometer (Zw) [6], a zero point offset can be corrected. Ramp generator [5] In the ramp generator [5], the control output incline is limited. Using the trimmer "t " [8], the time for the decreasing command value voltage is set. Characteristic curve generator [10] Using the trimmer "Gw" [9], the rated current of 1.6 A for the solenoid is set. In the characteristic curve generator [10], the command value signal is changed so that a linear command value pressure characteristic curve is created. Clock generator [12] In the clock generator [12], a frequency for the output stage adjusted to the command value is generated. Power output stage [11]-[14] Using the control output coming from the characteristic curve generator [10] and the clock frequency, the power output stage generates a PWM signal that is fed into the solenoid. The solenoid current is recorded and, in the current controller [11], compared with the control output and the difference is compensated. Fault recognition [15] Monitors the solenoid conductors with reference to cable break and short-circuit as well as over-current of the output stage. If there is an error, the green ready for operation display goes out.