Operating controls and keys, Mode key, Field arrow keys

3.0 Operating controls and keys.

3.1 Mode key

The Mode key is used to change the operating mode of the 4070A. When pressed, the LCD display is cleared and the question Mode? is displayed.

The Mode key acts as a shift type key in that the meaning of each button on the front panel changes to that described by the red wording beneath it. To enter Sweep mode, for example, first press the Mode key and then press the number 4 key.

You can exit the Mode screen by pressing the red Mode key again. The display returns to the previous mode unchanged. Some modes are available on the 4070A that are not printed on the front panel. To access these modes, press the Mode key, and then the Clear key to bring up a scroll menu from which you can select one of these extra modes.

3.2 Field arrow keys

Field arrow keys are used to move the cursor to the numeric entry field that you wish to edit. Each time the key is pressed, the cursor is advanced to the next field on the display. A flashing character indicates the cursor position.

When the cursor is advanced to a new field, it is placed at the last-used position within that field. You then use the

èor ç keys to move the cursor side-to-side within the field.

One of the valid cursor fields is "off". When the cursor is off, (i.e. there are no flashing characters anywhere) then all numeric values are frozen and cannot be changed until the cursor is switched back on. This feature is designed as a "lockout" function to safeguard parameter values from being changed by inadvertent key presses or turns of the rotary knob.

3.3 Recall / Store key

Recall/Store key is used to store or recall an instrument setup to or from 10 storage locations in non-volatile memory. By using the Store/Recall function, you can save all operating parameters so they can be quickly recalled even though the unit had been turned off. The offset voltage and currently selected RS232 baud rate are also saved.

If the instrument setup is saved while the unit is in Arbitrary Waveform mode, the currently loaded arbitrary waveform is stored to nonvolatile memory. Although mode parameters such as Clock Frequency, Level, etc. can be saved to 10 locations, the arbitrary waveform is always saved to/recalled from a single location. The entire waveform array of up to 32,768 points is saved.

To recall an instrument setup, press the Store/Recall key once. The LCD display will be cleared and the question: Recall (0-9)?Will appear, asking you to press a numeric key 0 to 9 to select one of ten available locations to use. You can abort this question without saving a configuration by pressing any key other than 0 to 9. If you then press the 5 keys, for example, the display will show Configuration recalled from location 5 to confirm the recall operation.

To save an instrument setup, press the Store/Recall button twice. The LCD display will be cleared and the line Store (0-9)?will appear, asking you to select one of ten available locations to store the configuration. You can abort the question without recalling a configuration by pressing any key other than 0 to 9.

NOTE: Location 0 is special. The instrument state stored to location 0 will be recalled on power-up. This includes the serial port baud rate.

3.4 Offset key

The Offset key is used to specify a DC offset voltage to be added to the output signal. When this key is pressed, the LCD display is cleared and the cursor is placed in a numeric field to enter the offset voltage. Both positive and negative voltages can be entered.

To exit the offset entry screen and return to the current mode, press the Offset key again. The offset voltage value can be entered in the same manner as any other numeric value. You can also use the wheel to modify a particular digit in the value. Any voltage within the range of -6.0 to +6.0 can be entered.

NOTE: The offset voltage specified is a 50O load value. This is the voltage that will appear across a 50O load connected to the SIG Out connector. If you are connecting the output to a high impedance load, the output voltage will be twice that entered.

BK Precision 4070A User Manual Rev.2.2