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2.5.3 Period Mode 

 
Period mode uses an internally generated reference clock to time the 
period between two edges on the input waveform.  It is selected as 
shown. 
 

 

 
The reference clock can be selected from 100MHz, 10MHz or 
1MHz.   The pair of edges that is timing is measured can be selected 
from: 
 

FALLING -> FALLING 

RISING -> FALLING 
FALLING -> RISING 

RISING -> RISING 

 
Note that for all practical purposes the first and last listed settings 
will yield the same answer, but there may be cases where being able 
to switch between these two settings is useful, in certain PWM 
waveforms for example. 
 
For most input periods, the 100MHz setting will suffice.  It offers a 
range of 0ns to 2.684s in steps of 10ns !  If you have a very slow 
input period, then selecting the 10MHz or 1MHz can increase this 
maximum period to 26.84s and 268.4s respectively, at the expense of 
timing resolution (down to 100ns and 1us respectively). 
 

Elan Digital Systems Ltd.

 20 

 

USBcount50 USER’S GUIDE Iss1

 

Summary of Contents for ES381

Page 1: ...ccard co uk website http www pccard co uk USBcount50 USER S GUIDE ES381 Important Notice Please refer to Safety Data 4 4 1 before using this instrument All Trademarks are duly acknowledged The USBcoun...

Page 2: ...tions For Non Stacked Configurations 14 2 3 2 2 Software For Non Stacked Configurations 14 2 4 Input Control 16 2 4 1 Input Supply 16 2 5 Counter Modes 17 2 5 1 General 17 2 5 2 Frequency Mode 19 2 5...

Page 3: ...4 4 4 Software 30 Elan Digital Systems Ltd 3 USBcount50 USER S GUIDE Iss1...

Page 4: ...equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there i...

Page 5: ...s Large dynamic range of counter means 1s integration setting can be used from 1KHz up to 100MHz i e no auto ranging required Period mode can use internal 1MHz 10MHz or 100MHz reference clocks coupled...

Page 6: ...el counter but to enhance flexibility several USBcount50s can be stacked together to make a combined 2 3 or 4 channel device In this case each counter is synchronised with the others so that the compo...

Page 7: ...simplified diagram of the USBcount50 CONTROLLER COUNTER STACK CONN BNC PSU DATA USB CONTROLLER USB ISOLATION BARRIER 8 BIT DAC Vsupply INPUT PROTECTION Figure 2 2 1 USBcount50 Architecture Diagram Ela...

Page 8: ...Now insert one of the long connectors from the top of one of the counters it doesn t really matter which one Push the pins of the connector into the top of the stacking connector from the side where...

Page 9: ...ason for this is that if you use the long connector the pins could be shorted out accidentally or you may touch the pins when the counter is connected to a high voltage and you could get an electric s...

Page 10: ...forced upward if it has simply press it down until it seats correctly see picture above for a guide as to the normal exposed connector depth after stacking Repeat this for each remaining counter addin...

Page 11: ...one at a time This may take a few seconds If you stack several counters but forget to connect say one of the counters to a USB port the software will warn you and will not run The software will displa...

Page 12: ...The about tab lists all the counters that have been found The list shows the serial number and revision data for each counter Elan Digital Systems Ltd 12 USBcount50 USER S GUIDE Iss1...

Page 13: ...the pins or use excessive force trying to mate the connectors Don t probe or drive any of the stack connector signals Avoid touching the stack connector pins signals during stacking Do make sure that...

Page 14: ...ay need to be powered externally Please refer to the hub s documentation for more details about the power available per port 2 3 2 2 Software For Non Stacked Configurations By default when you run USB...

Page 15: ...the first shortcut An instance of USBcount50 will run and configure the counter on COM4 Next double click the second shortcut and this will launch a second instance of USBcount50 but this time configu...

Page 16: ...range allows the user to match against common industry standard logic levels present in their circuit to be measured6 Elan Digital Systems Ltd 16 USBcount50 USER S GUIDE Iss1 6 Note that the input swi...

Page 17: ...the counter into STOP mode so that further readings cease During measurements the indicator in the reading panel changes colour depending on the state of the input signal or internal gate Yellow means...

Page 18: ...al frequency too high Try a shorter internal period or lower internal frequency If the counter waits for more than 2 seconds whilst in Period mode and no external signal has been detected the indicato...

Page 19: ...the 10s period may prove better at the expense of a slower reading update time The 0 1s period offers faster reading update rates but is only useful for input frequencies of greater than around 10KHz...

Page 20: ...cal purposes the first and last listed settings will yield the same answer but there may be cases where being able to switch between these two settings is useful in certain PWM waveforms for example F...

Page 21: ...y In the latter case by timing the period from edge to edge allows a very accurate measurement of low frequencies by simply inverting the period measured This is known as reciprocal mode The software...

Page 22: ...can be used if needed During installation three new hardware devices are detected The USBcount50 Composite Device first followed twice by the USBcount50 Controller itself The installation is automati...

Page 23: ...software takes care of all this at run time Start the USBcount50 software and you will see the following display9 To find out what the various buttons and knobs do simply hover over them for a brief...

Page 24: ...he USBcount50 Composite Device first followed by the USBcount50 itself It is vital to complete the installation of both devices11 After installation the device manager will look like this12 10 Include...

Page 25: ...software takes care of all this at run time Start the USBcount50 software and you will see the following display13 To find out what the various buttons and knobs do simply hover over them for a brief...

Page 26: ...get a run time error This could be caused by a much older version of the USBcount50 software that was installed previously but did not un install its registry hive settings To correct this go to the...

Page 27: ...Polycarbonate UL94V rated Size typical in mm 99 615 x 30 6 x 17 516 4 3 Environmental Humidity 80 non condensing General Operating Temperature 10 C to 45 C Ambient Storage Temperature 40 C to 80 C Amb...

Page 28: ...on has formed on the unit due to sudden temperature or humidity changes Never use test leads that are damaged or have insufficient or incomplete insulation Never allow any conductive part of any test...

Page 29: ...uaranteed 50MHz typically 100MHz with input signal suitable to trigger input threshold Master clock 12 50MHz initial accuracy 0 01 ageing and drift after 1 year 0 005 temp coefficient 0 005 oC Master...

Page 30: ...Me 2000 XP Recommended system Pentium Class 600MHz or better 16 Bit colour depth graphics or better with graphics acceleration 800x600 min screen resolution 256MBytes RAM USBcount50 registry hive HKEY...

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