Key; Set Key; Right-Hand Lcd Display Panel - IBM 7220 Instruction Manual

Dsp lock-in amplifier

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Figure 4-8, Setup Menu Mode - Left and Right-hand LCD Displays

In the setup menu mode, the left-hand SELECT keys adjacent to the left-hand

display cycle through a series of twelve setup menus. In general each menu allows

three controls to be adjusted, one via the right-hand side of the left-hand display and

the other two via the right-hand display. The setup menu description is shown on the

left-hand side of the left-hand display. Figure 4-8 makes this clear and the various

menus are discussed more fully in chapter 5.

When in the setup menu mode a further single press of the MENU key returns the

instrument to the normal Main Display mode.

4.1.06 90º Key

This key increments the reference phase shifter by 90º each time the key is pressed.

This key updates all frequency dependent parameters within the lock-in amplifier.

Press this key after any change to the External Reference frequency.

This panel is normally used to display two out of the set of fourteen possible

instrument outputs, with the keys on each side of it being used to make the selection.

In this mode it is also used to allow adjustment of the level of the output offsets

applied to the X and Y outputs. In addition, the panel is used in the setup menu mode

as described in section 4.1.05 above.

In the normal mode, the panel is divided vertically into two sections, with the output

descriptions shown on the upper line and the output values on the lower line. The

output type selection is made using the SELECT keys on each side of the upper line;

simply press the key repeatedly until the required output type is shown. Note that it is

not possible to set both sides of the display to the same output type. Figure 4-9 makes

this clear.

The SELECT keys associated with the right-hand display also allow easy switching

of the display between an output expressed as a percentage of full-scale and the

corresponding output expressed in volts or amps using the "simultaneous double

Chapter 4, FRONT AND REAR PANELS

4-5

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