Hoefer IEF100 - Manual (Page 20)

• p14
Steps
To edit any step parameter, turn the knob to highlight the parameter.
Press the knob, and turn the knob to set the desired value. Press the
knob again to enter the value, and move to the next field.
Each step has four fields that can be edited: the step type, a step value,
a step time, and step units:
Step Type Constant volt, gradient volt, constant watt.
Step Value Sets the maximum value of volt or watt depending
on step type.
Step Time Time in hours or volt-hours.
Step Units Hours (Hrs) or volt-hours (Vhrs).
Step Type and Step Value
Each step can be programmed in one of three different modes,
constant volt, gradient volt, or constant watt.
• In constant volt, the voltage remains constant thoughout the length
of the step.
• In gradient volt, the voltage will start at the end voltage of the
previous step and increase (or decrease) linearly over time to the
voltage entered in the current step. If the first step of the protocol is
a gradient volt step, the voltage will increase from 0.
• Gradient volt steps gradually increase the power being applied to
the IPG strips, resulting in more even heating of the strip over time.
• Constant watt steps will smooth out the heat generation as much
as possible over the course of the IEF separation. There will still
be localized heating due to different ion concentrations along the
length of the IPG strips.
• When using the constant watt step, the units for the step value
automatically change to watts.
• In constant watt steps, the IEF100 calculates the resistance, and
adjusts the voltage to maintain the constant watt setting.
Note: It is not recommended to set
a series of discrete volt steps. The
discontinuities between steps cause
spikes in power levels that tend to
increase the chances of burning strips.
Note: In some cases, the volt settings
may never be reached.
Note: If a constant watt step is
followed by a gradient volt step, the
gradient volt step will start from
0, and increase linearly to the set
voltage.