Device for producing dialysis liquid

A device for or of an extracorporeal blood treatment machine for producing and/or processing a dialysis liquid, the device comprising:

• a main fluid line for introducing osmotic water;
• at least one secondary fluid line connected to the main fluid line for supplying an additive into the osmotic water;
• at least one metering pump that sucks in the additive from at least one storage container in an intake phase and discharges the additive into the osmotic water in a discharge phase that serially follows the intake phase;
• an electric drive for operating the at least one metering pump;
• and
• a control or regulation unit for controlling or regulating the electric drive in such a way that the intake phase is shorter than the discharge phase,
• the electric drive comprising a stepper motor,
• the at least one metering pump comprising a magnetic sensor,
• the magnetic sensor operable to detect a position signal of the at least one metering pump, and
• the control or regulation unit configured to synchronize a start of the intake phase and/or of the discharge phase with the position signal.

A driving method of a metering pump for producing and/or processing dialysis liquid, the driving method comprising the steps of:

• detecting a position signal of a piston of the metering pump by a magnetic sensor;
• synchronizing a stepper motor with a start of an intake phase and/or of a discharge phase of the metering pump;
• computing a temporal resolution of control pulses of the stepper motor by a driving unit such that the stepper motor rotates at a higher rotation speed in the intake phase than in the discharge phase;
• and
• generating the control pulses in a required time grid.