Generating medical fluid for renal replacement therapy

A computer-readable medium comprising computer instructions which, when executed by a processor, cause the processor to perform a method for generating a medical fluid for renal replacement therapy, the method comprising:

• operating a first pump to convey a first fluid from a first container, which is arranged on a first scale, into a supply path that extends to an outlet for the medical fluid,
• operating a second pump to convey a second fluid from a second container, which is arranged on a second scale, into the supply path, to generate a mixture of the first and second fluids in the supply path,
• measuring, by a sensor, a composition-related parameter of the mixture,
• adjusting a pumping speed of at least one of the first and second pumps until the sensor measures a target value of the composition-related parameter,
• determining, based on first and second output signals from the first and second scales, a relation between a first weight change of the first scale and a second weight change of the second scale while the sensor measures the target value, and
• generating the medical fluid in the supply path, the generating comprising operating, based on the first and second output signals, the first and second pumps to achieve the relation between the first and second weight changes.

A system for generating a medical fluid for renal replacement therapy, said system comprising:

• a first scale;
• a first container arranged on the first scale;
• a second scale;
• a second container arranged on the second scale;
• a supply path, which is configured to receive a first fluid from the first container and a second fluid from the second container and extends to an outlet for the medical fluid;
• a first pump arranged to convey the first fluid from the first container into the supply path;
• a second pump arranged to convey the second fluid from the second container into the supply path to generate a mixture of the first and second fluids in the supply path;
• a sensor configured to measure a composition-related parameter;
• and
• a control device comprising circuitry, which is configured to perform a method, wherein the method comprises:
• operating the first pump to convey the first fluid from the first container, which is arranged on the first scale, into the supply path that extends to the outlet for the medical fluid,
• operating the second pump to convey the second fluid from the second container, which is arranged on the second scale, into the supply path, to generate the mixture of the first and second fluids in the supply path,
• measuring, by the sensor, the composition-related parameter of the mixture,
• adjusting a pumping speed of at least one of the first and second pumps until the sensor measures a target value of the composition-related parameter,
• determining, based on first and second output signals from the first and second scales, a relation between a first weight change of the first scale and a second weight change of the second scale while the sensor measures the target value, and
• generating the medical fluid in the supply path, the generating comprising operating, based on the first and second output signals, the first and second pumps to achieve the relation between the first and second weight changes;
• wherein the control device further comprises a signal interface, which is configured to output control signals for the first and second pumps and further configured to receive the first and second output signals from the first and second scales and a sensor signal representative of the composition-related parameter from said sensor.