TF930 Instruction Manual - English
Contents
1. declare that the TF930 3GHz Universal Counter with USB Interface meets the intent of the EMC Directive 2004 108 EC and the Low Voltage Directive 2006 95 EC Compliance was demonstrated by conformance to the following specifications which have been listed in the Official Journal of the European Communities EMC Emissions a EN61326 1 2006 Radiated Class B Immunity EN61326 1998 Immunity Table 1 referring to a EN61000 4 2 1995 Electrostatic Discharge b EN61000 4 3 2006 Electromagnetic Field c EN61000 4 4 2004 Fast Transient Performance levels achieved are detailed in the user manual Safety EN61010 1 Pollution Degree 2 ea Jalg CHRIS WILDING TECHNICAL DIRECTOR 1 May 2009 EMC Universal Counter This instrument has been designed to meet the requirements of the EMC Directive 2004 108 EC Compliance was demonstrated by meeting the test limits of the following standards Emissions EN61326 2006 EMC product standard for Electrical Equipment for Measurement Control and Laboratory Use Test limits used radiated emissions only were Class B Immunity EN61326 2006 EMC product standard for Electrical Equipment for Measurement Control and Laboratory Use Test methods limits and performance achieved are shown below requirement shown in brackets a EN61000 4 2 1995 Electrostatic Discharge 4kV air 4kV contact Performance B B b EN61000 4 3 2006 Electromagnetic Field 3V m 80 AM at 1kKHz 802. THURLBY THANDAR INSTRUMENTS TF930 3GHz UNIVERSAL COUNTER INSTRUCTION MANUAL Table of Contents Introduction 1 Specification 2 EMC 6 Safety 7 Connections 7 Manual Operation 9 Remote Operation 16 Maintenance 22 Introduction The TF930 is a portable battery operated universal counter with a large 0 5 10 digit liquid crystal display LCD The frequency range is from below 0 001Hz to 3GHz and measurement functions include frequency period ratio pulse width and count The instrument uses a high quality temperature compensated internal frequency reference which has a low aging rate and is stable to within 1ppm over the full temperature range Its short warm up time allows accurate measurements to be made even under portable battery powered conditions Input A has configurable coupling AC or DC input impedance 1MQ or 50Q attenuation 1 1 or 5 1 threshold fully variable and active edge and can be used for frequencies in the range 0 001Hz to over125MHz Input B is a nominal 50Q input for frequencies in the range 80MHz to 3GHz An External Reference input is provided and changeover from the internal timebase is automatic when an external reference standard is connected For frequency period and frequency ratio functions the instrument uses a reciprocal counting technique to provide high resolution at all frequencies 8 significant digits of answer are produced in a 1 second measurement time 9 digits in 10s and 10 digits
3. Values for TT and TO assume an input attenuation setting of 1 1 for 5 1 attenuation the effective levels will be the set value x 5 TA Use with DC coupling Threshold Level set to achieve auto triggering the threshold automatically adjusts to the average level of the waveform being measured no offset In all cases the threshold level is set irrespective of the position of the front panel control When remote state is first entered the trigger level is exactly as it had been set from the front panel the TO or TT command can be used to read this value corresponding to whether AC or DC coupling is currently set When the remote state is cleared the trigger level reverts to the setting determined by the current front panel control position Note that although mV resolution is provided offsets within the instrument result in the actual value being only approximately correct It is accurate enough to allow the setting of standard logic thresholds but if maximum sensitivity to small signals is required when DC coupled then some experiment may be required Using TO lt nr1 gt with DC coupling or TT lt nr1 gt with AC coupling may give unpredictable results it is up to the user to use settings consistent with each other and with the measurement application TA requires the user to first set DC coupling TA can be useful for automatically finding a useable measurement threshold for low frequency waveforms that require DC coupling or for higher fr
4. annunciator was flashing or not i e the measurement may not be valid Stopped by lt STOP gt or any other command N Next Result Query The measurement at the next LCD update provided the lt Measure gt annunciator is not flashing i e the next valid measurement Current Result Query The measurement at the most recent LCD update whether the lt Measure gt annunciator was flashing or not i e the measurement may not be valid The format of the response is the same for all forms of the query and is as follows NNNNNNN NNNeSEuu lt rmt gt where NN NN _ is the displayed answer with the decimal point in the corresponding position 11 characters e is the letter e for exponent is a plus or minus sign indicating the sign of the exponent E is the exponent value to give the answer in Hz or seconds uu is the units specifier Hz s_ _or__ _ is a space 2 characters If there is nothing to measure and the display is zero the response will be 0000000000 e 0_ _ lt rmt gt STOP Stops further measurements being sent in response to E or C any other command will also stop further measurements being sent as well as initiating the action of that command 19 Miscellaneous Commands IDN RST S LOCAL UD lt data gt UD Returns the instrument identification in the form lt name gt lt model gt 0 lt version gt lt rmt gt where lt name gt is the manufacturer s name lt model gt is the type of instrument
5. it is safe to leave the AC adaptor connected for long periods of AC powered operation though it is always good practice to disconnect the adaptor from the AC supply and the instrument if the instrument is not in use The instrument can be turned off and on with the AC adaptor connected using the OPERATE key If the instrument has been turned off using the OPERATE key then it will stay off wnen AC power is removed and when it is re applied If however the instrument is off when the AC adaptor power is applied and had last been powered off by removing the AC power then the instrument will automatically power on and when the AC adaptor power is removed it will power off again This is useful when the instrument is part of a test set up which is switched on and off with a mains power master switch If the instrument is running on battery or USB power when the AC adaptor power is applied then AC adaptor power will take precedence in powering the instrument and when the AC adaptor power is removed the instrument will continue to operate from the battery or USB power It is always good practice to disconnect the adaptor from the AC supply and the instrument if the instrument is not in use for long periods Switching On The instrument can be switched on and off with alternate presses of the OPERATE key whatever power source is being used At power on the default operating conditions are always as follows Input A Frequency AC coupling 1MQ inp
6. DC coupling is selected it will allow for very slow signals by waiting forever for an input transition the display will continue to show the last value Input Impedance 1MQ is the default and can be used with both AC and DC coupling It can be used directly or in conjunction with x1 x10 or x100 oscilloscope probes as appropriate to the signal amplitude Select 50Q for higher frequencies and where the signal source impedance is 50Q to minimise spurious counting caused by reflections Input Attenuation 1 1 no attenuation is the default Select 5 1 for larger signals particularly if noise is significant When measuring standard logic signals use 1 1 attenuation for 1 8V or lower CMOS and 5 1 for TTL or higher voltage CMOS Additional attenuation can be achieved by attenuating the signal externally before being presented to the counter a x10 oscilloscope probe can be used with the 1MQ input impedance or a 50Q attenuator can be used with the 50Q input impedance to preserve matching Input Polarity Rising edge pulse High is the default setting with this setting Frequency and Period measurements start and finish on the rising edge and Count is the total number of rising edge occurrences The Width measurement is from rising edge to falling edge which together with the Period measurement yields the calculated Ratio High Low time and Duty High time as a percentage of Period measurements If the polarity is changed to falling edge pulse
7. Temperature Stability Initial Oscillator Adjustment Error Oscillator Ageing Rate Calibration adjustment range Measurement Functions Frequency Input A or Input B A Input Frequency Range B input Frequency Range Resolution Period Input A or Input B A Input Period Range B input Period Range Resolution Pulse Width Modes Input A only Functions Pulse Width Range Averaging Resolution Total Count Input A only Count range Minimum pulse width Frequency Ratio B A Resolution Measurement Time 50MHz 10MHz TCXO with electronic calibration adjustment Better than 1ppm over rated temperature range lt 0 2ppm at 21 C lt 1ppm first year gt 8ppm lt 0 001Hz DC coupled to gt 125MHz 80MHz to gt 3000MHz up to 10 digits see below or 0 001Hz 8ns to 1000s DC coupled 333ps to 12 5ns up to 10 digits see below Width high width low ratio H L high time to low time and duty cycle 40ns to 1000s Automatic within measurement time selected up to 50 pulses 20ns for one pulse up to 1ns or 10 digits with multiple pulse averaging 0 01 for Ratio H L and Duty Cycle 1 to 9 999 999 999 8ns Equal to the resolution of the two frequency measurements If the ratio exceeds ten digits six digits and the exponent are displayed Selectable as 100s 10s 1s or 0 3s The instrument displays the average value of the input signal over the measurement time selected updated ever
8. and lt version gt is the revision of the firmware installed Identify Query Returns the instrument model number only Resets the instrument to its power on default values and sets the Threshold Level to the midway AC position Also empties remote I O queues and clears error status Reset measurement Performs the same operation as pressing the front panel RESET key under the same conditions Status Query Reads and returns the instrument status The response is sent immediately The response is xy lt rmt gt where x and y are numeric digits expressed in ASCII format The first digit is the status byte and is a bit significant value in the range 0 to 7 The meaning of each bit is as follows bitO External standard connected bit 1 An error has occurred bit2 A continuously updated bit indicating that an input signal is being counted It does not necessarily guarantee that there is sufficient signal for an accurate result The second byte contains the error number of the last error that occurred The value is cleared to zero after each status query Error numbers are as follows 0 No error has occurred since the last status query 1 Acommand syntax error one or more commands ignored Returns the instrument to local operation and unlocks the keyboard Store user data maximum string length 250 characters The string may contain any character between 20H and FFH inclusive except 3BH Can be used to give the instrument a
9. drivers be copied first to a suitable location on the hard disc and then installed from there when the first unit is attached The operating system can then subsequently find the drivers without requiring the CD Installation of the interface drivers is achieved by connecting the instrument to a PC viaa standard USB cable The Windows plug and play functions should automatically recognise the addition of new hardware attached to the USB interface and if this is the first time the connection has been made prompt for the location of a suitable driver Two layers of driver are required and the standard Windows prompts will appear twice Provided that these prompts are followed correctly Windows will install the appropriate drivers and establish a COM port within the PC The number of the new COM port will depend upon the number of previously allocated COM ports within that PC Note If the plug and play function reports that a later version of the driver is already installed keep the later version the TF930 will operate satisfactorily with the later version A unique code embedded in each instrument ensures that it will receive the same COM port number each time it is attached to the PC irrespective of which physical USB port it is connected to Adifferent unit will prompt again for installation of the drivers the first time it is attached and will receive a different COM port number The operating parameters of the COM port must be set to matc
10. is galvanically connected to the body of the BNC inputs and will therefore be at earth ground potential when the USB port is connected to a desktop PC However to maintain user safety under all other circumstances it is essential that no input is connected to a voltage above 30Vdc or 30Vrms with respect to earth ground which is the limit of Safe Extra Low Voltage SELV by IEC definition Note that although the inputs will withstand short term accidental connection to an AC line voltage up to 250Vrms 50 60Hz users will be at risk if the instrument ground is connected to such hazardous voltages The instrument shall be disconnected from all voltage sources before it is opened for any adjustment replacement maintenance or repair Any adjustment maintenance and repair of the opened instrument under voltage shall be avoided as far as possible and if inevitable shall be carried out only by a skilled person who is aware of the hazard involved Do not wet the instrument when cleaning it The following symbols are used on the instrument and in this manual ae Direct Current CAUTION refer to accompanying documentation Damage to the instrument may occur if these precautions are ignored meaning that the marked terminal is connected to accessible conductive parts Adaptor Charger The adaptor charger supplied has a universal input voltage rating of 100 240VAC 50 60Hz It is a Class Il double insulated device fully approved to E
11. on the two inputs and dividing the B result by the A result The result of the calculation is as accurate as the measurements Each signal can be any frequency within the permitted range of the respective input If the ratio is so large that the decimal point cannot be shown on the display then the result is shown with six digits and an exponent Measurement Time Measurement time is changed using the left lt 4 and right gt MEASUREMENT TIME keys the selected time being shown by the appropriate annunciator in the display With a suitable signal connected to the selected input the Measure annunciator will flash in the display to indicate that the signal has been detected the Measure annunciator continues to flash until a true result for that selected measurement time is displayed at which point it stays on continuously Further display updates then show the running average of the signal behaviour over the last 0 3s 1 update every measurement 1s 2 updates per second 10s 1 update per second or 100s 1 update every 2 seconds depending on the selected measurement time Note that if a 1s 10s or 100s measurement time is selected starting or restarting a measurement gives a true result with generally 7 digits resolution after 0 3s 8 digits after 1s 9 digits after 10s and finally 10 digits after 100s The units and the decimal point position are automatically adjusted to give the result in the most convenient units Pressing the HOLD key
12. Low Frequency and Period measurements will start and finish on the falling edge and Count will totalise the occurrences of falling edges If the waveform being measured has a slow rising edge but fast falling edge setting the Polarity to falling edge might be advantageous in reducing measurement jitter Changing the Polarity for Width measurements however will change the interpretation of Ratio and Duty and should only be used with care Low Pass Filter The default setting is for no filter If Filter In is selected the FILT annunciator will show in the display the nominal cut off frequency is 50kHz The filter is particularly useful for low frequency measurements but with an adequate input signal it can be helpful at frequencies up to 200kHz or more Trigger Level Threshold Adjustment The trigger level control is associated with two yellow LED lamps which indicate the signal balance at the output of the Ainput amplifier Their brightness varies from bright to dim depending on the relationship between the trigger threshold and the average value of the input signal When the threshold setting matches the average value of the input signal they are of equal brightness If a signal is applied and the instrument is not counting move the threshold control towards the dimmer of the two lamps Note that the smaller the input signal level the more critical this setting becomes When AC coupling is selected the default configuration a threshold feedb
13. MHz 1GHz Performance B A and 1 4GHz to 2GHz Performance B A 1V m 2 0GHz to 2 7GHz Performance B A Note The TF930 is a sensitive measuring instrument and if subjected to a sufficiently large RF field will count its frequency At lower field strengths a measurement might be disturbed particularly if the applied signal level is small This is much more likely to be a problem with the B input than the A input In all other respects the instrument will operate correctly Performance A in fields up to 3V m c EN61000 4 4 2004 Fast Transient 0 5kV peak signal inputs Performance B B Adaptor Charger This AC adaptor charger has been designed to meet the requirements of the EMC Directive 2004 108 EC Compliance was demonstrated by meeting the test limits of the following standards Emissions EN55022 radiated and conducted Class B Immunity Test methods limits and performance achieved were a EN61000 4 2 1995 Electrostatic Discharge 4kV air 4kV contact Performance B B b EN61000 4 3 2002 Electromagnetic Field 3V m 80 AM at 1kHz Performance A A c EN61000 4 11 2004 Voltage Interrupt 30 reduction 10ms Performance B B 60 reduction 100ms Performance C C d EN61000 4 4 2004 Fast Transient 1kV peak AC line Performance B B e EN61000 4 5 1995 Surge 1kV line to line 2kV line to ground Performance B B f EN61000 4 6 1996 Conducted RF 3V 80 AM at 1kHz AC line only DC Ou
14. N 60950 1 2001 UL 60950 UL listing E138754 and AS NZS CISPR 2002 C Tick Connections Front Panel Connections Input A For frequencies in the range 0 001Hz DC coupled to gt 125MHz Input impedance selectable between 1MQ 25pF and 50Q Maximum allowable input 1Vrms 1 1 attenuation or 4Vrms 5 1 attenuation for 1MQ 25pF input 1Vrms above 300kHz for 50Q input AC coupled Maximum input with respect to earth ground 4 is 30Vdc or 30Vrms 50 60Hz Input B For frequencies in the range lt 80MHz to gt 3GHz Input impedance 509 Maximum allowable input 1Vrms AN Maximum input with respect to earth ground is 30Vdc or 30Vrms 50 60Hz EXT REF IN For a 10MHz signal from an external reference standard only Input impedance gt 100kQ AC coupled Maximum allowable input TTL 5Vpp CMOS or 2Vrms sinewave Maximum input with respect to earth ground 4 is 30Vdc or 30Vrms 50 60HZz Rear Panel Connections DC IN DC power to operate and or recharge the instrument is connected via the 1 3mm power socket Use ONLY the AC adaptor charger provided by TTi with the instrument Use of any other power source will void the warranty USB The USB port accepts a standard USB cable The Windows plug and play functions should automatically recognise that the instrument has been connected The instrument will automatically be powered by the USB host if the AC adaptor charger is not connected USB power can be used without the USB conn
15. ack mechanism is engaged with the threshold control providing a small offset above or below the average signal level Normally the control should be set with the marker at the midway position marked AC 11 This setting should count most signals but on very small signals some slight adjustment may be needed for maximum sensitivity The usable adjustment range from this position is approximately 50mV 1 1 attenuation or 200mV 5 1 attenuation If DC coupling is in use then the feedback mechanism is disconnected and the threshold is directly adjusted by the control over the range of nominally 0 to 2V 1 1 attenuation or 0 to10V 5 1 attenuation There is some over range at each end of the control The Threshold control should be adjusted in the direction which brings both yellow LED lamps on and then finely adjusted to get the most stable measurement For waveforms with slow edges adjusting the threshold will of course affect the Width and associated Ratio and Duty cycle measurements but not Frequency Period and Count The Threshold control should always be adjusted slowly as there is a noise rejection filter with a long time constant in the circuit Input B Input B is used for frequency measurements in the range 80MHz to gt 3GHz The input impedance is nominally 50Q The maximum input voltage from 20MHz to 3GHz is 1Vrms and the input is diode clipped with inputs over 250mVrms The input is protected against temporary accidental con
16. d as character codes OOH to 20H inclusive with the exception of the LF character OAH lt WHITE SPACE gt is ignored except in command identifiers e g DN is not equivalent to IDN The high bit of all characters is ignored The commands are case insensitive Each query produces a specific lt RESPONSE MESSAGE gt which is listed with the command in the remote commands list Command List This section lists all commands and queries implemented in this instrument The commands of the TF830 all of which have been implemented on this instrument are identified by TF830 on the right hand side of the Remote Command Summary list next section Each command is completely executed before the next command is started The following nomenclature is used lt rmt gt lt RESPONSE MESSAGE TERMINATOR gt lt n gt A single digit number lt nr1 gt An integer number Function Selection F lt n gt Sets the measurement function to lt n gt where n corresponds to the following B Input Period A Input Period A Input Frequency B Input Frequency Frequency Ratio B A A Input Width High A Input Width Low A Input Count A Input Ratio H L A Input Duty Cycle Oo ON Da FF ON gt a O The new function is selected immediately and a new measurement is started 17 AC Set A Input to AC coupling DC Set A Input to DC coupling Z1 Set A Input to 1MQ input impedance Z5 Set A Input to 50Q input impedance A1 Set A Inpu
17. e Extra Low Voltage Note that although the inputs will withstand accidental short term connection to an AC line voltage up to 250Vrms 50 60HZz users will be at risk if the instrument ground is connected to such hazardous voltages Battery Operation The instrument is fitted with rechargeable NiMH cells with a capacity of 2500mAH giving typically 24 hours use when fully charged Charging is done using the AC adaptor supplied see below The Bat annunciator shows in the top right hand corner of the display when the instrument is operating from its internal battery this changes to Lo Bat when approximately 10 of battery life remains During battery operation the instrument is turned on and off with alternate presses of the OPERATE key USB Power The instrument can also be powered from a PC s host port even if the instrument s battery is flat the battery will not however be recharged from USB power Connect the instrument s rear panel USB connector to a PC via a standard USB cable the Windows plug and play function should automatically recognise the addition of new hardware and if this is the first time the connection has been made prompt for the location of a suitable driver The disk supplied with the instrument contains drivers for various versions of Windows follow the PC s on screen prompts to load the appropriate driver there are two separate stages Note If the plug and play function reports that a later version o
18. e function The displayed value can be frozen with the HOLD key the count continues in the background The count can be restarted set to zero using RESET the 2 function of HOLD When the count reaches the maximum of 9999999999 the next active edge restarts the count from zero The WIDTH measurement can be set to measure either the High time above the threshold or Low time below the threshold by choosing the appropriate polarity setting see earlier Input A Configuration Options section Selecting RATIO with the A input active shows the ratio of High time to Low time RATIO H L or vice versa according to the polarity setting Low inactive time is calculated by subtracting the measured High active time from the period Selecting DUTY shows the High time or Low time depending on polarity setting expressed as a percentage of the total period Function Selection B input With Input B 80MHz 3GHz selected only the FREQUENCY and PERIOD functions can be used attempts to select WIDTH COUNT or DUTY will be ignored by the firmware the B annunciator will flash briefly to indicate that this is not a valid selection and the existing setting will remain unchanged Selecting RATIO with Input B selected by a long press on the PERIOD key is valid but sets the instrument to a RATIO B A mode Frequency B Frequency A not RATIO H L as described for the A input The ratio B A is obtained by making simultaneous frequency measurements
19. ection being used for remote control The instrument can only be powered via its USB port if the connection is properly enumerated it is therefore not possible to use adaptors which only provide DC power through a USB connector Manual Operation Power The instrument has three possible sources of power the internal rechargeable battery DC input from the AC DC adaptor charger supplied referred to in this manual as the AC adaptor or USB power from a USB host port on a desk top or portable PC The AC adaptor if present will be used in preference to USB power or the battery without the AC adaptor USB will take preference over the battery only if neither the AC adaptor nor USB power is present will the battery be used The instrument software remembers the power up cause and conditions and acts intelligently at loss of AC adaptor or USB power to ensure that the battery is not discharged unintentionally Power up and power down operation for all possible combinations of conditions are detailed in the sections that follow Safety Warning The TF930 is a safety class III instrument by IEC classification When the instrument is operated from its internal battery AC adaptor or USB port of a portable ungrounded PC all accessible parts will be at the same voltage potential as the outer of the BNC input sockets to maintain user safety it is therefore essential that no signal input is connected to a voltage above 30V dc or 30Vrms the limit of Saf
20. equency waveforms with very small duty cycles There is no equivalent front panel setting 18 TC Threshold Level to centre position TN Threshold Level to negative pulse position TP Threshold Level to positive pulse position These three commands are only included to maintain compatibility with the TF830 and are used to set the threshold level to one of three preset positions available under remote control on that counter Centre is equivalent to the threshold level control at the midway AC position Negative pulse and positive pulse are equivalent to 60mV and 60mV respectively with AC coupling selected the only coupling available on the TF830 Measurement Commands M lt n gt Sets the measurement time to lt n gt where n corresponds to the following 1 0 3s 2 1s 3 10s 4 100s The new measurement time is selected immediately and a new measurement is started E Every Result Query Measurement results are sent continuously at the interval set for the measurement time 0 3s 1s 10s or 100s Since these are measurement time intervals all results will be valid measurements Stopped by lt STOP gt or any other command C Continuous Result Query Measurement results are sent continuously at the rate at which the LCD is updated for the selected measurement time every 2s 1s 0 5s or 0 3s for measurement times of 100s 10s 1s or 0 3s respectively Measurements are sent whether the lt Measure gt
21. er TTi TF830 Universal Counter can also be used on the TF930 allowing existing programs to be used However the TF930 has no address capability and those commands associated with ARC Addressable RS232 Control will be accepted but ignored Remote Local Operation At power on the instrument will be in the local state in this state all keyboard operations are possible When the instrument receives a command the remote state will be entered and the Rem annunciator will show in the display In this state the keyboard is locked out except for the Local RESET and OPERATE keys and remote commands only will be processed The instrument may be returned to the local state by a long press of the Local RESET key the Rem annunciator will go off However the effect of this action will remain only until the instrument receives another character from the interface when the remote state will once again be entered Sending the LOCAL command also exits the remote state USB Interface 16 The USB interface of this instrument is implemented using a USB to UART device which then communicates with a UART inside the main processor Once the device drivers are installed on a PC the device will appear to be a standard COM port as if it were inside the PC This port can then be accessed by Windows applications in exactly the same way as a standard port If it is anticipated that more than one TF930 might be connected to the same PC it is recommended that the
22. f the driver is already installed keep the later version the TF930 will operate satisfactorily with the later version The instrument will only be powered via its USB port if the connection is properly enumerated so it is not possible to use adaptors which only provide DC power through a USB connector USB power takes priority over battery power to preserve battery charge the Bat or Lo Bat annunciator goes off to indicate this If the instrument is off when the USB connection is enumerated then the instrument will automatically power on and when the USB power is removed it will power off again If the instrument is running on battery when the USB connection is enumerated then USB power will take precedence in powering the instrument and when the USB connection is removed the instrument will continue to operate from the battery The instrument can be turned off and on with USB power connected using the OPERATE key USB power can be used without the USB connection being used for remote control AC Adaptor Operation The AC adaptor is connected to the rear panel 1 3mm socket marked DC IN only the AC adaptor supplied with the instrument should be used When the AC adaptor is powered the red EXT POWER lamp will be lit whether the instrument is on or off if the battery is being charged the yellow CHARGING lamp will also be lit The instrument has intelligent charging control to optimise performance and battery life plus various protection measures
23. h that it is within 0 2ppm parts per million after warm up in an ambient of 21 C At ambient temperatures other than 21 C the additional error is less than 1ppm over the whole operating range 5 C to 40 C The ageing rate is less than 1ppm in the first year and decreases exponentially with time The recommended calibration period is 1 year see Maintenance section External Reference 14 If measurements are to be made which require still greater accuracy than can be obtained using the TCXO an external 10MHz frequency standard may be applied to the External Reference input The signal should be TTL 3Vpp to 5Vpp CMOS or 1 to 2Vrms sinewave The external reference is used to phase lock the internal oscillator and must only be a high accuracy 10MHz signal It is not possible to make ratiometric measurements by applying a non standard signal The presence of an external reference signal of adequate amplitude is automatically detected and phase lock is attempted the Ext Ref display annunciator is shown when the external reference is detected Note that if an improper signal is applied then the internal oscillator will be pulled off frequency and measurement accuracy significantly impaired Noise When measuring low amplitude low frequency sinewaves noise will cause variations in the displayed result at each display update Users should make every effort to maximise the amplitude of the signal presented to the input The internal noise of
24. h the internal requirements of the instrument baud rate 115200 8 bits no parity The default values are set in the Properties page in Device Manager but many communications programs override the default settings and each will need to be correctly configured Remote Command Format Serial input to the instrument is buffered in an input queue which is filled under interrupt in a manner transparent to all other instrument operations The instrument will send XOFF when the queue is nearly full XON will be subsequently be sent when sufficient space becomes available for more data to be received This queue contains raw un parsed data which is taken by the parser as required Commands and queries are executed in order and the parser will not start a new command until any previous command or query is complete Responses to commands or queries are sent immediately there is no output queue Commands must be sent as specified in the commands list and must be terminated with the command terminator code OAH Line Feed LF Commands may be sent in groups with individual commands separated from each other by the code 3BH The group must be terminated with command terminator OAH Line Feed LF Responses from the instrument to the controller are sent as specified in the commands list Each response is terminated by the lt RESPONSE MESSAGE TERMINATOR gt ODH Carriage Return CR followed by OAH Line Feed LF lt WHITE SPACE gt is define
25. in 100s with a granularity of less than 2 counts in the least significant digit Indicators show measurement input configuration amp function measurement time amp status external reference connection low battery and the units of the measurement which may be Hz kHz MHz ns us ms or s The instrument has a USB interface which allows it to be remotely controlled using serial communication via a computer s USB port The remote commands of its predecessor instrument the TF830 are compatible with the TF930 command set The instrument will also automatically be powered from a standard USB port when connected whether remote control is in use or not The instrument operates from internal rechargeable NiMH batteries which give typically 24 hours operating life The universal AC charger supplied will recharge the batteries in less than 4 hours and can be used for continuous AC operation Connection to a standard USB port will also power the instrument but not charge the batteries This instrument is fully compliant with EN61010 1 Safety and EN61326 EMC standards Input Specifications Input A Configurable options Input coupling Input impedance Attenuation Active edge Low pass filter Trigger threshold Input Impedance Frequency Range Trigger Threshold DC coupled AC coupled Input Signal Range 1MQ DC coupled 1MQ AC coupled 50Q AC coupled Sensitivity Input B Input Impedance Frequency Range Sens
26. itivity Input Signal range External Reference Input Input Impedance Frequency Signal Level Maximum Input Voltage Specification AC or DC 1MQ or 50Q 1 1 or 5 1 Rising or falling or width high or low Filter In 50kHz cut off or Out Variable threshold for both DC and AC coupling 1MQ 25pF DC or AC coupled or 50Q nominal AC coupled only lt 0 001Hz to gt 125MHz 1MQ DC coupled lt 30Hz to gt 125MHz 1MQ AC coupled lt 500kHz to gt 125MHz 50Q AC coupled 0 to 2V 1 1 attenuation or 0 to 10V 5 1 attenuation Average 50mV 1 1 attenuation or 250mV 5 1 attenuation 0 to 3 3V max 1 1 attenuation or 1 to 12V max 5 1 attenuation 1Vrms or 3Vpp max 1 1 attenuation or 4Vrms or 12Vpp max 5 1 attenuation 1Vrms above 300kHz Sinewave 15mVrms 30Hz to 100MHz 25mV to 125MHz at optimum threshold adjustment 509 nominal AC coupled lt 80MHz to gt 3GHz Sinewave 12mVrms 80MHz to 2GHz 25mVrms to 2 5GHz 50mVrms to 3GHz lt 0dBm recommended 13dBm 1Vrms maximum gt 100kQ AC coupled 10MHz TTL 3Vpp to SVpp CMOS or 1 to 2Vrms sinewave Inputs A and B and AN 30VDC 30Vrms 50 60Hz with respect to earth ground L External Reference Note that the inputs will not be damaged if subjected to an accidental short term connection to a 50 60Hz line voltage not exceeding 250Vrms or 250V DC Timebase Measurement Clock Internal Reference oscillator Oscillator
27. m input voltage and onset of clipping will depend on the coupling attenuation and input impedance settings and are given in the Specification The input is protected against temporary accidental connection of mains voltages up to 250Vrms at 50 60Hz Input A Configuration Options The default configuration options for Input A at power on are AC coupling 1MQ input impedance 1 1 attenuation rising edge polarity and no filter with the Threshold control set to mid position a measurement should be possible with the majority of waveforms Changes to the configurations will however be necessary for certain waveforms e g DC coupling and low pass filter in circuit will improve measurement of low frequencies Input Coupling AC coupling is the default and can be used with either input impedance setting Select DC coupling for very low frequencies lt 30HZ or if the waveform duty cycle is very low DC coupling should normally be used with the input impedance set to 1MQ selection of 50 is allowed but because a 50kQ protection resistor is fitted in parallel with the coupling capacitor the actual impedance will be much higher than 50Q until the input frequency is greater than approximately 300kHz This configuration can be useful to avoid charging up the coupling capacitor on asymmetrical waveforms When AC coupling is selected the instrument will assume there is no signal and set the display to 0 0 after about 1 second if no transition occurs When
28. n identifying or information data string which can be queried using the UD command Examples of use are Serial No calibration due date owner s name etc Returns user data from store Remote Command Summary The commands of the TF830 all of which have been implemented on this instrument are identified by TF830 on the right hand side FO F1 F2 F3 F4 F5 F6 F7 F8 F9 AC DC 20 B Input period A Input period TF830 A Input frequency TF830 B Input frequency TF830 Frequency ratio B A TF830 A Input width High TF830 A Input width Low TF830 A Input count TF830 A Input ratio H L A Input duty cycle A input AC coupled A input DC coupled Z1 Z5 A1 A5 ER EF FI FO L TT lt nr1 gt TO lt nr1 gt Values assume TO TT TA TC TP TN M1 M2 M3 M4 E C N STOP 1 IDN R RST S LOCAL UD lt data gt UD A input 1MQ input impedance A input 50Q input impedance A input 1 1 attenuator A input 5 1 attenuator Rising edge A Input only Falling edge A Input only Filter In A Input only TF830 Filter Out A Input only TF830 Low frequency mode TF830 Trigger threshold set to nnnn mV 300 to 2100mvV DC coupling Trigger auto average offset by nn mV 60 to 60mV AC coupling 1 1 attenuator for 5 1 attenuation thresholds will be set value x5 Returns current TO Threshold setting in mV Returns current TT Threshold setting in mV Trigger a
29. nection of mains voltages up to 250Vrms at 50 60Hz The signal being measured should have a 50 source impedance to avoid standing waves which could give spurious results The input cable should be kept as short as possible and 50 coaxial cable should be used Note that because of the wide bandwidth of this input signals mixed with other components which fall within the frequency and sensitivity range of the input can cause incorrect counting externally attenuating or filtering the signal before presenting it to the counter may help to obtain a correct reading In particular when attempting to count the highest frequency component of a signal with broadband noise or other interference an external high pass filter may be needed especially with small signals above 2GHz Function and Measurement Time Selection Function and measurement time are selected using the keys immediately below the display The annunciators in the display show the current settings Function Selection A input 12 Pressing the FREQUENCY PERIOD or WIDTH key will immediately set the instrument to that function pressing and holding the key down for more than 1 second will change the function to COUNT RATIO or DUTY respectively the 2 function printed above the key in blue the selected function is shown by the appropriate annunciator in the display FREQUENCY and PERIOD measurements are directly displayed in the appropriate units COUNT is a simple totalis
30. o about 1000 samples per second It accumulates up to 50 such samples spread across the selected gate time computes the average and displays the result Each sample has a resolution of 20ns and the average is displayed with a resolution up to 1ns The values for duty cycle and ratio H L better thought of as the ratio active inactive are computed from the average width and the accurately known period The display resolution presented in these modes is a reasonable representation of the probable measurement accuracy Ratio B A This mode is entered by a long press of the WIDTH RATIO key when the B input is selected It takes as nearly simultaneous capture and continue measurements of both input signals as possible Because each measurement terminates on a transition of its respective signal the two measurements are not exactly simultaneous unless the signals are synchronously related This is not likely to be an issue unless the signals are significantly frequency modulated Note that this method is completely different to the previous model the TF830 which implemented ratio B A mode by counting the B input using the A signal as the reference timebase Timebase and Other Accuracy Considerations The following is intended as a guide to determine the limits of measurement error Internal Oscillator The instrument has an internal temperature compensated crystal oscillator TCXO which has been factory set from a Rubidium reference standard suc
31. re and continue counting and means there is no dead time at the end of each gate interval This allows successive measurements to be concatenated without incurring a one clock cycle uncertainty at the intermediate points of the measurement The instrument uses this capability to give a rolling update in the display more often than the selected gate time Each of these updates show the average value of the input frequency over the time interval equal to the selected gate time immediately preceding it being displayed 13 If the signal has frequency modulation the instrument will display the average value across the gate time the modulation is almost certainly not synchronous with the gate so there will be small random variations in the displayed value If the signal has amplitude modulation its amplitude at the trough of the modulation must exceed the sensitivity threshold of the input Counting deeply modulated signals requires both considerable amplitude and a sensitive adjustment of the trigger threshold Width Duty Cycle and Ratio H L Measurements When Width mode is selected the instrument continues to use the capture and continue method to measure the signal period It cannot measure the width of the active part of the signal this way because by definition there are gaps between the measurements while the signal is in the inactive state Instead it measures the width of a sample of individual cycles of the input signal at a rate up t
32. rol All capabilities can be controlled remotely and measurements read through a USB port The instrument can be powered but the battery cannot be charged by the USB host Interface Serial port emulation over USB Current consumption lt 95mA lt 5mA if AC adaptor power is present Command set Instrument specific TF830 compatible Power Requirements The instrument has fixed internal rechargeable batteries and is supplied with a universal voltage external mains adaptor with interchangeable UK Euro Australian and US power connectors Battery Type Three 2500mAh NiMH cells Battery Operating Life Typically 24 hours Low Battery Indicator Lo Bat shows in display when approximately 10 of battery life remains Recharge Time lt 4 hours Adaptor Supply range 85 to 240V 50 or 60 Hz Power consumption SW max at DC input to unit 15VA max at AC adaptor input charging General Display 10 digit LCD 12 5mm high 0 5 Annunciators show input configuration operating mode measurement units and gate time Operating Range 5 C to 40 C 20 to 80 RH Storage Range 20 C to 60 C Environmental Indoor use at altitudes up to 2000m Pollution Degree 2 Size 260mm W x 88mm H x 235mm D Weight 950 gms plus 170 gms AC adaptor Electrical Safety Complies with EN61010 1 EMC Complies with EN61326 EC Declaration of Conformity We Thurlby Thandar Instruments Ltd Glebe Road Huntingdon Cambridgeshire PE29 7DR England
33. t to 1 1 attenuation A5 Set A Input to 5 1 attenuation ER Set rising edge of waveform as start of measurement EF Set falling edge of waveform as start of measurement FI Low Pass Filter In on FO Low Pass Filter Out off When remote state is first entered the filter stays set as it was in the local state When remote state is cleared the filter setting remains as it was in the remote state L Low frequency mode Applicable to TF830 only Command accepted but ignored by TF930 which is automatically in low frequency mode while DC coupling is selected Threshold Commands TO lt nr1 gt Use with AC coupling Threshold automatically adjusts to the average level of the waveform being measured offset by lt nr1 gt mV where lt nr1 gt is a number in the range 60 to 60 if no sign is present lt nr1 gt is assumed to be positive TO Returns the current TO Threshold value in the form SnnnnmV lt rmt gt where S is the sign nnnn is the Threshold voltage in mV and mV is the units specifier S is only present if the sign is negative TT lt nr1 gt Use with DC coupling Threshold set to a level of lt nr1 gt mV where lt nr1 gt is a number in the range 300 to 2100 if no sign is present lt nr1 gt is assumed to be positive TT Returns the current TT Threshold value in the form SnnnnmV lt rmt gt where S is the sign nnnn is the Threshold voltage in mV and mV is the units specifier S is only present if the sign is negative
34. th water or a mild detergent WARNING TO AVOID ELECTRIC SHOCK OR DAMAGE TO THE INSTRUMENT NEVER ALLOW WATER TO GET INSIDE THE CASE TO AVOID DAMAGE TO THE CASE OR DISPLAY WINDOW NEVER CLEAN WITH SOLVENTS 22 TITZ Thurlby Thandar Instruments Ltd Glebe Road Huntingdon Cambridgeshire PE29 7DR England Telephone 44 0 1480 412451 Fax 44 0 1480 450409 e mail sales tti test com web site www tti test com Book Part No 48581 1400 Issue 2
35. the instrument is random with a significant low frequency 1 f element Selecting a longer gate time will reduce the effect of this noise and allow the user to see the extremes of the variation and establish an approximate average This method may be less effective on signals with externally induced intermittent or non random noise such as supply frequency interference Signal level In general it is obvious from the variations of the display value that a signal is too small for reliable counting but on the B input at high frequencies especially over 2GHz the effect of insufficient signal can be very subtle A signal 2 or 3dB below the true threshold might only show an error in the eighth digit in a consistent way that is not obviously detectable for true accuracy users are recommended to ensure that the signal level meets the published specification even though the instrument is typically notably more sensitive 15 Remote Operation The USB interface allows the instrument to be controlled using serial communications via a computer s USB port The instrument is supplied with a disk containing drivers for various versions of Windows Any driver updates are available via the TTi website www tti test com The disk also contains a text file with information and details of the software installation procedure The remote command format and the remote commands themselves are detailed later in this section The remote commands of the earli
36. tput connection lt 3m therefore not tested Performance A A Performance Definitions The definitions of performance criteria are Performance criterion A During test normal performance within the specification limits Performance criterion B During test temporary degradation or loss of function or performance which is self recovering Safety Universal Counter This instrument is Safety Class III according to IEC classification and has been designed to meet the requirements of EN61010 1 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use This instrument has been tested in accordance with EN61010 1 and has been supplied in a safe condition This instruction manual contains some information and warnings which have to be followed by the user to ensure safe operation and to retain the instrument in a safe condition This instrument has been designed for indoor use in a Pollution Degree 2 environment in the temperature range 5 C to 40 C 20 80 RH non condensing It may occasionally be subjected to temperatures between 5 and 10 C without degradation of its safety Do not operate while condensation is present Use of this instrument in a manner not specified by these instructions may impair the safety protection provided WARNING All accessible parts will be at the same voltage as the outer of the BNC input sockets In particular note that the shell of the USB connector
37. ut impedance 1 1 attenuation rising edge polarity no filter 0 3s measurement time and no measurement hold the associated annunciators will show in the display The threshold level is set by the position of the Threshold control If the RESET key is held down whilst the instrument is switched on using the OPERATE key all the annunciators will be shown in the display and for 2 seconds the main display area will show the revision number of the installed firmware After 2 seconds all the segments of the display will show as a functional display check until the RESET key is released Press to Measure With the instrument off pressing any of the measurement function switches FREQUENCY PERIOD or WIDTH will power up the instrument and set the selected function all other conditions are defaulted as described above The instrument will then function normally and respond to all key presses After a period of about 15 seconds with no key presses the instrument will automatically power down this conserves the battery if operating on battery power Input Selection and Configuration Input A or Input B are selected with alternate presses of the INPUT SELECT key an annunciator in the display indicates which input is active Input A 10 Input A can be used for frequencies in the range 0 001Hz to gt 125MHz and has a number of configuration options described below which allow it to count a wide range of waveform shapes and amplitudes The maximu
38. uto average without offset Set DC coupling first Trigger centre TF830 Trigger positive TF830 Trigger negative TF830 Measurement time 0 3s TF830 Measurement time 1s TF830 Measurement time 10s TF830 Measurement time 100s Every result query TF830 Continuous result query Next result query TF830 Current result query TF830 Stops further measurement results being sent Identifier query Returns model number only TF830 Instrument identification Returns full instrument identification Reset measurement TF830 Reset instrument to default settings Status query TF830 Returns instrument to local operation Store user data Returns lt data gt 21 Maintenance The Manufacturers or their agents overseas will provide a repair service for any unit developing a fault Where owners wish to undertake their own maintenance work this should only be done by skilled personnel in conjunction with the Service Information available from the Manufacturers or their agents overseas Calibration Calibration at the time of delivery is guaranteed as in the Specification However annual routine recalibration is recommended to maintain the high accuracy that this instrument offers Recalibration may be carried out without dismantling the instrument using a suitable precision frequency standard details are provided in the Service Information Cleaning If the instrument requires cleaning use a cloth that is only lightly dampened wi
39. will freeze the displayed measurement and the Hold annunciator will be shown Hold is cancelled by a second press of the HOLD key The measurement continues in the background while Hold is selected Switching between FREQUENCY and PERIOD measurement on the same input or switching between WIDTH RATIO H L and DUTY Input A will immediately convert the present measurement otherwise a change of function including a change of input or measurement time will initiate a new measurement A new measurement may also be started without a change of function or measurement time by using RESET the 2 function of the HOLD key Measurement Principles Frequency and Period The instrument uses a measurement method generally known as reciprocal counting After each measurement interval gate time ends it waits for the completion of the present cycle of the input signal before capturing the count data It has therefore measured the time taken by a whole number of input cycles with a resolution of one cycle of its internal measurement clock It then calculates the average period of the input signal by dividing the total time by the number of input cycles the frequency is the reciprocal of this period value This method yields much more accurate results at low frequencies than the traditional method of counting input cycles for an exact gate time The hardware captures count values without either stopping or resetting the counters This is known as captu
40. y 2s 1s 0 5s or 0 3s respectively The hardware captures the count values and continues measuring without any dead time Resolution The displayed resolution depends upon measurement time and input frequency The basic resolution of period is 8 digits for every 2 seconds of measurement time Frequency resolution is the reciprocal of period resolution Usable resolution can be reduced by noise at low frequencies Accuracy Measurement accuracy is timebase accuracy measurement resolution 2 counts Operating Facilities Noise Filter The Filter key controls a low pass filter with a cut off frequency of about 50kHz to assist in obtaining stable readings at low frequencies Hold Pressing the Hold key will hold the current measured value in the display with the Hold indicator on until the Hold key is pressed again The measurement continues in the background when Hold is on Along press on the Hold key clears old data and restarts the measurement Intelligent Power Switching The unit automatically selects the best available power source of AC adaptor USB or battery Intelligent switching avoids discharging the battery overnight when operated from externally switched AC power A press to measure facility allows a quick measurement to be made by pressing a function select key which will power the instrument up in the corresponding function The instrument will automatically switch off 15 seconds after the last key press Remote Cont
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