Model 7002Switch System Instruction Manual - Advanced Test ...

Getting Started5. Use the keypad to key in the desired scan count andpress ENTER.6. Use EXIT to back out of the menu structure.Channel LayerFactory power-on defaults set Channel Spacing to Manualand the channel count to the scan list length (number of channelsin the scan list). For most scans, using the scan listlength as the channel count is appropriate. With manualchannel spacing selected, the STEP key (or STEP LED) isused to manually control the scan.Available channel spacing selections are summarized as follows:TIMER – In general, a channel is scanned each time the programmedtimer interval expires.EXTERNAL – In general, each external trigger (via the ExternalTrigger BNC connector) selects the next channel in thescan.GPIB – In general, each bus trigger (GET or *TRG) selectsthe next channel in the scan.MANUAL – In general, each time the STEP key is pressed(or the STEP LED is clicked) the next channel in the scan isselected.TRIGLINK – In general, each trigger received via the TriggerLink selects the next channel in the scan.IMMEDIATE – Channels will continue to scan immediatelyand not wait for any of the previous channel spacing events.HOLD – Holds operation in the channel layer and preventschannels from being scanned.NOTE: EXTERNAL and TRIGLINK are beyond the scopeof Getting Started. Refer to Section 4 to use these selections.Perform the following steps to change the channel spacing:1. Press SCAN CONFIGURATION to display the CON-FIGURE SCAN menu.2. Place the cursor on CHAN CONTROL and press EN-TER to display the CHANNEL CONTROL menu.3. Place the cursor on CHANNEL SPACING and pressENTER to select the SELECT CHAN SPACING menu.4. Place the cursor on the desired channel spacing selectionand press ENTER. Note that selecting the TIMERwill require that a time interval be entered.5. Use EXIT to back out of the menu structure.NOTEA typical method to control channel scanningis to use DELAY. A delay can be setfor each slot. This delay is invoked aftereach channel of that slot is closed. By settingChannel Spacing for Immediate, thescan rate will, for the most part, be controlledby the DELAY period. See paragraph4.13 to set DELAYs.Step 3. Starting the ScanAssuming the instrument is in the idle state (ARM indicatoron VFD off), a scan will not start until the STEP key ispressed (or the STEP LED is clicked). This takes the instrumentout of the idle state (ARM indicator on). The scan willthen proceed according to how it was programmed in Step 2.A scan can be aborted at any time by pressing the OPENALL key (or clicking the OPEN ALL LED).3.10 Introduction to IEEE-488.2 and SCPIThe following paragraphs discuss fundamental informationconcerning operation over the IEEE-488 bus. Detailed informationon operating the instrument from over the bus is containedin Section 5 of this manual.SCPI overviewIEEE-488.2 defines a syntax for sending data to and from instruments.It also defines a set of Common Commands thatare used to perform basic operations such as reading statusregisters, providing triggers and resetting the instrument todefault conditions.3-16