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FTA200 Pump Resolution

Stepper motor driven pumps move the syringe plunger by linear increments. The diameter of the plunger determines the actual volume displaced. Changing the syringe diameter will therefore scale the displacement up or down. The pump motion stays calibrated by entering the correct diameter on the Pump | Syringe tab.

The FTA200 pump is available with a choice of two stepper motors. One has an increment of 1.8 degrees per step and is the faster motor and the other has one half the motion, 0.9 degrees, and provides higher resolution but slower top speed. If in doubt, you can read the part number from the motor on the instrument.

  • PK243M. The "M" signifies microstepping or high resolution. The remaining characters in the part number specify coil voltage and are unimportant. The PK243M is the standard pump motor.

    • 0.9 degrees per step
    • 11584.9 controller or micro steps per millimeter (enter this number in Driver Setup on the Pump | Syringe tab)
    • 1448.1 motor steps per millimeter
    • 1145 max motor steps per second
    • 0.1117 microliters per motor step with 10cc syringe
    • 128 microliters per second max practical dispense rate with 10cc syringe
  • PK243. No "M" in number. This is the optional motor.

    • 1.8 degrees per step
    • 5,792.4 controller steps per millimeter (enter this number in Driver Setup)
    • 724.05 motor steps per millimeter
    • 1145 max motor steps per second
    • 0.2234 microliters per motor step with 10cc syringe
    • 256 microliters per second max practical dispense rate with 10cc syringe

Notice the values specific to a 10cc syringe. The 10cc syringe is almost, but not quite, the syringe length of Hamilton glass Gas Tight syringes:

  • 10cc plastic syringe: 61.8 millimeters long
  • Hamilton Gas Tight: 60.0 millimeters long

Volumetric resolution and dispense rates scale linearly with volume, assuming constant syringe length. For three practical Hamilton syringes, we have

  • 1000 microliter:

    • Length = 60 millimeters
    • Plunger resolution with PK243M = 1448.1 steps per millimeter
    • Total steps per syringe with PK243M = 86,886
    • Volume resolution with PK243M = 0.0115 microliters per motor step
    • Max rate with PK243M = 13.19 microliters per second
    • Plunger resolution with PK243 = 724.05 steps per millimeter
    • Total steps per syringe with PK243 = 43,443
    • Volume resolution with PK243 = 0.0230 microliters per motor step
    • Max rate with PK243 = 26.38 microliters per second
  • 500 microliter:

    • Length = 60 millimeters
    • Plunger resolution with PK243M = 1448.1 steps per millimeter
    • Total steps per syringe with PK243M = 86,886
    • Volume resolution with PK243M = 0.00575 microliters per motor step
    • Max rate with PK243M = 6.59 microliters per second
    • Plunger resolution with PK243 = 724.05 steps per millimeter
    • Total steps per syringe with PK243 = 43,443
    • Volume resolution with PK243 = 0.0115 microliters per motor step
    • Max rate with PK243 = 13.19 microliters per second
  • 250 microliter:

    • Length = 60 millimeters
    • Plunger resolution with PK243M = 1448.1 steps per millimeter
    • Total steps per syringe with PK243M = 86,886
    • Volume resolution with PK243M = 0.00288 microliters per motor step
    • Max rate with PK243M = 3.29 microliters per second
    • Plunger resolution with PK243 = 724.05 steps per millimeter
    • Total steps per syringe with PK243 = 43,443
    • Volume resolution with PK243 = 0.0575 microliters per motor step
    • Max rate with PK243 = 6.59 microliters per second