HOLD - disables either ARM:SOURce1 or ARM:SOURce2. This is the reset source for ARM:SOURce2.

IMMediate - arms the digitizer immediately after INITiate[:IMMediate] is received. This choice is only valid for ARM:SOURce1. If IMMediate is specified, HOLD must be specified for ARM:SOURce2. IMMediate is the reset value for ARM:SOURce1.

Note An active reference oscillator is required for the digitizer to recognize and accept an arm signal from any source.

Setting the Arm Signal When the arm source is INTernal1, INTernal2, or EXTernal1, the digitizer Slope arms on a specified level of a positive-going or negative-going input signal.

For these sources, the digitizer must be informed of the slope on which to arm (positive-going, negative-going, or either (for INTernal<n >)). This is done with the command:

ARM[:STARt]:SLOPe[<n >] <edge >

The <edge > settings are:

POSitive - arm on a positive-going edge of the input signal.

NEGative - arm on a negative-going edge of the input signal.

EITHer - arm on either edge of the input signal (INTernal<n > sources only).

The command is used with the arm source and arm level commands as shown:

!set arm source to INT1 or INT2

ARM[:STARt]:SOURce[<n >] <source >

!set positive or negative transition

ARM[:STARt]:SLOPe[<n >] <edge >

!set arm input voltage level

ARM[:STARt]:LEVel[<chan >]:POSitive <voltage >

or

ARM[:STARt]:LEVel[<chan >]:NEGative <voltage >

The arm slope command allows you to specify a positive transition, a negative transition, or either transition. When a positive transition is specified, the digitizer is armed when the increasing signal on the channel reaches the specified level. When a negative transition is specified, the digitizer is armed when the decreasing signal on the channel reaches the specified level. When "EITHer" is specified, the digitizer is armed when the input signal enters or exits the defined window. Refer to Figure 3-6.

Chapter 3

Understanding the HP E1429 Digitizer 115

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Image 115
HP E1429A manual Set positive or negative transition