A medical fluid injector system (450) is disclosed that may utilize one or more of flow rate determination logic (130), injection volume determination logic (132), display control logic (134), drive ram motion control logic (136), and pressure monitoring logic (138). The flow rate determination logic (130), injection volume determination logic (132), and display control logic (134) each may utilize a concentration input (172, 192, 202) to calculate flow rates, injection volumes, and generate multi-color graphics, respectively, for a simultaneous injection configuration. The drive ram motion control logic (136) may utilize both a target pressure and a monitored pressure to derive a velocity for advancing a drive ram. The pressure monitoring logic (138) may provide a monitored pressure value for the drive ram control logic (136), where this monitored pressure value may be derived from the input power being used to advance a drive ram and the drive ram velocity.