HP E1429A manual Arm Level Range

The Arm Level Range

When setting the input voltage level which arms the digitizer, the levels are restricted to the current signal range as set by the expected value parameter of the CONFigure or MEASure command, or as set by the SENSE:VOLTage:RANGE command. Table 3-1 lists the digitizer’s signal ranges.

Note When level arming, arms that occur because of multiple passes through the arm level are ignored until the trigger count is reached.

Setting the Arm Delay There is an inherent delay of typically 230 ns plus an amount of sample period uncertainty from when an arm is received, to when the arm is accepted. When the digitizer is taking only post-arm readings, a delay in addition to the inherent delay can be specified with the command:

ARM[:STARt]:DELay <period >

The range for <period > is based on the frequency of the reference clock. If

T is the reference period, then the arm delay period is expressed as:

0 to 65534T in steps of T

66540T to 655350T in steps of 10T

Using the digitizer’s internal 20 MHz reference, this is:

0 to 3.27 ms 3.32ms to 32.76 ms

Note Appendix A - "Specifications" contains additional information on the inherent arm delay.

Setting the Arm Count The arm count is the number of reading cycles (bursts) the digitizer will take on each channel before it returns to the idle state. The arm count is specified with the command:

ARM[:STARt]:COUNt <count >

The range for <count > is:

1through 65,535 or INFinity (post-arm readings only)

1through 128 (pre-arm and post-arm readings)

Chapter 3 Understanding the HP E1429 Digitizer 117