VXI VT1538A user manual Agilent E1538A Enhanced Frequency/Totalize/PWM SCP

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read pulse widths from CVT

start algorithm

Figure 12. Measure Pulse Width

read puls width on chs 46&47 Algorithm reads the pulse widths on channels 146 and 147 and returns these values in CVT elements 46 and 47

ALG:DEF ’ALG1’,’writecvt( I146, 46 ); writecvt( I147, 47 );’

INIT

. . .

SENS:DATA:CVT? (@46,47)

*RST

SENS:FUNC:PWID 4,(@146,147)

To measure pulse width on channels 46&47

Measure Pulse Width This means that the E1538 will measure the width of the logic 1 portion of a pulse. The pulse width is sent to the algorithm in units of seconds. To measure the high portion of a pulse (positive going edge to negative going edge) set the channel input polarity to INP:POL NORM,(@<ch_list>). To measure the low portion of the pulse (negative going edge to positive going edge) set the channel input polarity to INP:POL INV,(@<ch_list>).

The value returned to an algorithm can be from 5μSec to 1 Second with 59.6nSec resolution.

To configure channels to measure pulse width use the command [SENSe:]:FUNCtion:PWIDth <avg_count>,(@<ch_list>)

•<avg_count> sets the number of pulses to average when forming the pulse duration value. More counts give more accurate readings, but slower response to changing pulse widths.

•<ch_list> specifies the channels that will read pulse widths

20 Agilent E1538A Enhanced Frequency/Totalize/PWM SCP

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Contents VT1538A VXI Technology, Inc Introduction Support Resources User’s and Scpi Programming Manual Page Agilent E1538A Enhanced Frequency/Totalize/PWM SCP About this ManualIntroduction Identifying the Plug-on Important Setting Configuration Switches Switch Location and Example SettingsInstallation Connecting To The Terminal ModuleRecommended Signal Connections E1419A Option 11 Terminal Module ConnectionsInput and Output Characteristics Recommended Connections and Voltage LimitsVRS Mode Input Operation SCP Channels 0 & 1 only E1538A Input/Output CharacteristicsProgramming With Scpi Commands Shows the VRS mode input characteristicsConfiguring I/O Direction Setting the Input Threshold LevelDetermining the Input Threshold Level Inppol NormReading Static Digital State To set channels 40 through 43 to input digital statesTotalize Positive or Negative Edge State Changes Init SENSDATACVT? @44About Period Frequency Measurements SENSDATACVT? @45 SENSDATACVT? @45 Agilent E1538A Enhanced Frequency/Totalize/PWM SCP Agilent E1538A Enhanced Frequency/Totalize/PWM SCP Sense Quadrature Position Sensfuncquad 0,@148,149RPS Example of Rotational Velocity Sense Sense Rotational VelocityControlling Output Polarity Output Static Digital StateVariable Width Pulse Per Trigger Variable Width Pulse Train PWM Variable Frequency Fixed Width Pulse Train FM Variable Frequency Square-Wave Pulse Train Rotationally Positioned Pulse Output Rotational Pulse Command Usage Algupdate Init Example of variable position, preset width RST Sensfuncrvel 12,MISS,@140Variable Position, Width Preset by Time Example of variable width by angle, preset position Example of variable width by time, preset position Fixed Position, Variable Width by AngleALGSCALAR’ALG1’,’Width2’,.010 Stepper Motor Control Use the command Stepping mode valuesSensfuncvolt @100 Full Step Mode, Full and Half Speed, 4-Channel Page RST and *TST important Scpi Command Reference Command Syntax For newer Units onlyCommand Syntax For newer Units only Discussed INPutPOLarity INPutPOLarity?Parameters CommentsLevel can be set to a resolution INPutTHResholdLEVelINPutTHResholdLEVel? OUTPutPOLarity OUTPutPOLarity?Send with VXIplug&play Function hpe14XXcmdReal64Q SENSeFREQuencyAPERture Related Commands Sensfreqaper SENSeFREQuencyAPERture?SENSeFREQuencyLIMitLOWer Init Related Commands INPutPOLarity SENSeFREQuencyLIMitLOWer?SENSeFUNCtionCONDition SENSeFUNCtionFREQuency SENSeFUNCtionPERiodSENSeFUNCtionPWIDth SENSeFUNCtionQUADratureSENSeFUNCtionRVELocity RPS SENSeFUNCtionTOTalize SENSePERiodAPERture SENSePERiodAPERture? SENSePERiodLIMitUPPerInit SENSePERiodLIMitUPPer? SENSePERiodMODERelated Commands SENSePERiodMODE SENSePERiodMODE?SENSePERiodNPERiods SENSePERiodNPERiods? SENSePERiodRANGeUPPerSend with VXIplug&play Function hpe14XXcmdInt32Q SENSeTOTalizeRESetMODE SENSePERiodRANGeUPPer?RST Condition is Send with VXIplug&play Function hpe14XXcmd SENSeTOTalizeRESetMODE? SOURceFMSTATeSOURceFMSTATe? Send with VXIplug&play Function hpe14XXcmdInt16QSOURceFUNCtionRPULse SOURceFUNCtionSHAPeCONDition SOURceFUNCtionSHAPePULSeSOURceFUNCtionSHAPeSQUare SOURceFUNCtionSTEPperComments Send with VXIplug&play Function hpe14XXcmd Relationship of minvel, and maxvel SOURcePULMSTATe Usage See Stepper Motor Control onSOURcePULMSTATe? SOURcePULSePERiodSOURcePULSePERiod? SOURcePULSeWIDThSOURcePULSeWIDTh? SOURceRPULsePOSitionANGLe33,554,430 to 33,554,430 SOURceRPULsePOSitionANGLe? SOURRPULseVARTypeUsage SOURRPULseVARType? SOURceRPULseWIDThANGLeSOURceRPULseWIDThANGLe? SOURceRPULseWIDThTIME00000787 to SOURceRPULseWIDThTIME? Specifications General SpecificationsFrequency Measurement Pulse Width Measure Rotational Pulse Source