The EMEC PRISMA Dosing Pump incorporates Stepper Motor control for excellent precision, repeatability and reliability of chemical dosing. The PRISMA diaphragm and stepper motor microprocessor control the stroke and suction cycle to a pitch resolution of 1:4800, and ensure precise control of the stroke frequency and therefore a low discharge pulsation, even when dosing viscous substances. With the exclusive SLOW MODE functionality of the PRISMA Stepper Motor metering pumps, the stroke speed during the suction cycle can be reduced to 75%, 50% and even 25%. This feature facilitates the adaptation of the pump to the metering medium and increases the reliability and venting of high viscosity dosing media.