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Model TT339-0700

 

 

4-Wire Isolated Frequency Transmitter w/USB 

 

 

 

 

 

Acromag, Inc. Tel: 248-295-0880  

 

            

  

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 26 

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http://www.acromag.com 

 

Measurement Techniques 

 
 

 

This transmitter utilizes one of two measurement techniques at any given time to 

measure the input frequency and switches dynamically between the two 

measurement techniques as needed to maximize system performance. These two 

measurement techniques are referred to as Technique A and B as listed in the Flow 

Chart on the previous page.  

 

Technique A:

  For measuring input frequencies less than 25000Hz. This 

measurement technique uses the input capture as a gate, and counts the number of 

system clock cycles (32MHz) between two input captures. The nature of this 

method results in reduced input resolution with increasing input frequency. Input 

resolution can be calculated as follows: 1 part in [32MHz / Input Frequency(Hertz)]. 

 

Note:

 When using Technique A, it is possible that the input signal period is greater 

than the Output Update rate. In the event that the Output Update is reached before 

a new input capture has occurred (since previous Output Update), the output of the 

transmitter will reflect the last measured input frequency (unchanged from 

previous Output Update). Conversely, multiple input captures can occur when the 

input signal period is less than the Output Update rate. Each new input capture 

contributes to the Cumulative Moving Average (CMA). The frequency calculated 

based on the CMA is added to the FIFO queue on every Output Update.  

 

Technique B:

  For measuring input frequencies greater than 20000Hz. This 

measurement technique counts the number of input captures within a user-

configured time span (Output Update). Due to this method’s dependence on Output 

Update, the input resolution increases with increasing Output Update. Input 

resolution can be calculated as follows:  1 part in [32MHz * Output 

Update(milliseconds)]. 

 

TROUBLESHOOTING 

Diagnostics Table 

 

 

POSSIBLE CAUSE 

POSSIBLE FIX 

Cannot Communicate with Transmitter via USB… 
Output shifts off-range when you connect USB… 
Output Erratic, Not operational, or at Wrong Value… 
Transmitter fails to operate or exhibits an output shift… 

A missing USB Isolator 

could cause a ground 

loop between a 

grounded input sensor 

and earth ground at the 

connected PC’s USB 

port. 

Without a USB isolator, a ground loop is possible 

between a grounded input signal source and earth 

ground of the PC USB port. It is best to connect to 

USB via a USB isolator for this reason, and for 

increased safety and noise immunity. Use an isolator 

like the Acromag USB-ISOLATOR. Otherwise, use a 

battery powered laptop to configure the transmitter 

which does not normally earth ground its USB port.  

 

Содержание TT339-0700

Страница 1: ...WM Pulse Input Universal Current Voltage Output USER S MANUAL ACROMAG INCORPORATED 30765 South Wixom Road Wixom MI 48393 2417 U S A Copyright 2014 Acromag Inc Printed in the USA Data and specifications are subject to change without notice Tel 248 295 0880 Fax 248 624 9234 email sales acromag com 8500 948M ...

Страница 2: ... 6 Sensor Input Connections 7 Output Connections 9 Power Connections 10 Optional Bus Redundant Power Connections 11 Earth Ground Connections 12 USB Connections 13 CONFIGURATION SOFTWARE 14 Quick Overview Android 14 Quick Overview Windows 15 OPERATION STEP BY STEP 17 Connections 17 Configuration 19 Calibration Optional 23 BLOCK DIAGRAM 24 How It Works 24 Flow Chart 25 Measurement Techniques 26 TROU...

Страница 3: ...nent sensor or software failure in the design of any type of control or monitoring system This is very important where property loss or human life is involved It is important that you perform satisfactory overall system design and it is agreed between you and Acromag that this is your responsibility The information of this manual may change without notice Acromag makes no warranty of any kind with...

Страница 4: ...anges up to 21mA or 10 5V DC without rewiring Supports normal or reverse acting output Fast response time and high accuracy Space saving 17 5mm 0 7 inch unit with pluggable terminals for convenient wiring Redundant power ready rail local 1500V isolation 3 way power input output Shock 25g and vibration 4g resistant Mounts on Type T DIN rail Wide ambient operation 40 to 80 C CE compliant UL cUL Clas...

Страница 5: ...ilt upward so that it may be lifted from the rail when prying the spring clip back with a screwdriver To attach a module to T type DIN rail angle the top of the module towards the rail and place the top groove of the module over the upper lip of the DIN rail Firmly push the module downward towards the rail until it snaps into place Removal To remove a module from the DIN rail first separate the in...

Страница 6: ...ved from their sockets by prying outward from the top with a flat head screwdriver blade Strip back wire insulation 0 25 inch on each lead and insert the wire ends into the cage clamp connector of the terminal block Use a screwdriver to tighten the screw by turning it in a clockwise direction to secure the wire 0 5 0 6Nm torque Since common mode voltages can exist on signal wiring adequate wire in...

Страница 7: ...p TIP Input power and output terminal blocks are a plug in type and can be easily removed to facilitate module removal or replacement without removing individual wires Sensor wires are connected directly to the module input terminals at the bottom of the module the spring loaded DIN clip side Transmitter input signals are isolated from output and power Observe proper polarity when making input con...

Страница 8: ... results If sensors are inherently connected to ground use caution and avoid making additional ground connections which could generate ground loops and measurement error REFERENCE Input excitation EXC is 5VDC Bipolar mode for zero crossing signals Unipolar mode for non zero crossing signals Internal pull up pull down resistors are 2 7KΩ 1KΩ and connect to 5V FRTN ...

Страница 9: ...ect the longest distance between the field transmitter output and the remote load as shown above Additionally shielded twisted pair wiring is recommended for best results An output connection to earth ground will help protect the circuit from damage in noisy environments WARNING For compliance to applicable safety and performance standards the use of twisted pair output wiring is recommended Failu...

Страница 10: ...2 32VDC This voltage must never exceed 36VDC peak or damage to the transmitter may result Variations in power supply voltage between the minimum required and 32VDC maximum has negligible effect on transmitter accuracy Note the placement of earth ground at input power The power cable shield and DC should ideally be grounded closest to the transmitter Only one end of the connection should be grounde...

Страница 11: ...he bus power connector may also be used to redundantly power modules allowing a backup supply to maintain power to the module s should the main supply at TB4 fail This transmitter comes equipped with the bus connector 1005 063 shown below This connector allows modules to snap together side by side along the DIN rail and share these connections To complete connection to power an optional bus termin...

Страница 12: ...ctions Drawings for Input Output and Power and note the position of earth ground Earth ground should be applied at the input power minus terminal DC The input and output circuits are shunted to earth ground applied at the power minus terminal via internal isolation capacitors Avoid inadvertent connections to earth ground at other points than those indicated as this could drive ground loops and neg...

Страница 13: ... signal isolator that supports USB Full Speed operation 12Mbps IMPORTANT USB logic signals to the transmitter are referenced to the potential of the transmitter s input ground This ground is held in common with USB ground and USB cable shield ground Thus an isolator is required when the input signal is grounded and the transmitter is connected to the USB port of an earth grounded PC The use of an ...

Страница 14: ...on and select the desired model Swipe left or right to view more diagrams No connection is required to view the diagrams Android requires user permission to access external hardware If the Device List displays No Device Permission select this device and when prompted to give permission to access the USB device tap OK Configuration Tab CONFIGURE I O Once connected the app will automatically read yo...

Страница 15: ...e Frequency or Duty Cycle Select the Pull Up Down depending on the input sensor type Enter the Cutoff Frequency Inputs below the Cutoff Frequency are measured as 0Hz Enter the Debounce time The input must be steady for this length of time before the transmitter will conduct a measurement Enter the number of Samples to Average This controls the number of samples included in the FIFO queue first in ...

Страница 16: ...ure the transmitter output signal and enter the measurement in the input field provided Click the Submit Measurement button to send the calibration to the transmitter For output full scale endpoint adjustment click the Full Scale button to open the full scale configuration popup Use a current meter or digital volt meter to accurately measure the transmitter output signal and enter the measurement ...

Страница 17: ...as a function of the IR voltage drop produced in the resistor recommended for current outputs Calibration Configuration Connections Connect Input Optional Connect a function generator or sensor at TB1 if you want to verify the operation of the transmitter s intended application Refer to Sensor Input Connections section for example input wiring and configurations Connect Power Wire 12 32VDC power t...

Страница 18: ...ow at left If you happen to be connected to more than one transmitter via a USB hub you can use the device scroll field to select another transmitter using the serial information suffix of the model number to discern one transmitter from another Select a transmitter from the drop down menu When you click on a transmitter name from the drop down menu the software will automatically attempt to open ...

Страница 19: ...e menu in the upper left hand corner of the window and selecting Save As Select the Threshold The Threshold should be selected based on the type of input signal the transmitter is measuring Select Bipolar when the input signal is zero crossing Select Unipolar when the input signal is non zero crossing There are two levels of hysteresis available for both Bipolar and Unipolar options The hysteresis...

Страница 20: ...no input is captured within this duration the transmitter will measure 0Hz For example a 0 25Hz Cutoff Frequency would configure the transmitter to wait 4 seconds before measuring 0Hz Enter the number of Samples to Average This transmitter captures and saves samples in a FIFO first in first out queue The number of samples in this queue is equal to the number of Samples to Average The FIFO queue is...

Страница 21: ...or upon reaching the Cutoff Frequency is to update the output immediately to 0Hz Left unchecked the time before the output signal reaches 0Hz will be a function of the number of Samples to Average and the Output Update rate Select the Output Range The output terminals of this module are universal and may drive DC current or voltage in the ranges 20mA 0 20mA 4 20mA 10V 0 10V 5V and 0 5V Approximate...

Страница 22: ...mitter s operation by clicking on the Start Polling button of the TEST I O Section of the page to trigger the software to periodically read the input and display its value in the field to the right of the polling toggle button Note the simulated lamp next to the button flashes each time the input is sampled Click Stop Polling to stop polling the input Other Configuration Controls Restore Factory C...

Страница 23: ... your selections to the transmitter by clicking the Send I O Config button Click the Output Cal Instructions button to begin output calibration and enable the Output Zero Scale and Full Scale buttons For output zero scale endpoint adjustment click the Zero Scale button to open the zero scale configuration pop up Use a current meter or digital volt meter to accurately measure the transmitter output...

Страница 24: ...aw power from USB The USB port ground is common to the input circuit ground The USB port ground of most PC s is also common to the USB cable shield and earth ground Input sensors could be grounded or ungrounded For this reason it is recommended that USB signals be isolated when connected to a PC to prevent a ground loop from occurring between the PC earth ground and a grounded input sensor which w...

Страница 25: ...umulative Moving Average CMA Output Update Override No Set Measurement to 0Hz Yes Calculate Frequency based on Cumulative Moving Average or Capture Count and add to FIFO Queue Set Measurement to FIFO Queue Running Average Update Output based on scaled Measurement Yes Reset Capture Count and Cumulative Moving Average No Using Technique A Measurement 25KHz Measurement 20KHz Yes No Switch to Techniqu...

Страница 26: ...input captures can occur when the input signal period is less than the Output Update rate Each new input capture contributes to the Cumulative Moving Average CMA The frequency calculated based on the CMA is added to the FIFO queue on every Output Update Technique B For measuring input frequencies greater than 20000Hz This measurement technique counts the number of input captures within a user conf...

Страница 27: ... signal with respect to its range and reduce or increase it as required to drive the output within its linear operating range A fully Over Range or Under Range signal can be driven by a sensor fault such as an open or broken sensor lead If you are not isolating USB check for a ground loop between a grounded sensor and earth ground of the PC USB port Cannot Measure Input Signal Input may be wired i...

Страница 28: ...itter USB Isolator USB Isolator Order USB ISOLATOR USB Signal Isolator USB A B Cable 4001 112 Instructions 8500 900 This kit contains a USB isolator and a 1 meter USB A B cable for connection to a PC This isolator and cable are also included in TTC SIP see above USB A B Cable USB A B Cable Order 4001 112 USB A B Cable 4001 112 This is a 1 meter USB A B replacement cable for connection between a PC...

Страница 29: ...Model TTBUS KIT This kit contains one each of the following terminals DIN Rail Bus Connector 1005 063 for 17 5mm TT Modules Left Side terminal block female connector 1005 220 Right Side terminal block male connector 1005 221 Two End Stops for 35 mm DIN Rails 1027 222 not shown This module was shipped with the first item included in this kit DIN Rail Bus Connector 1005 063 and this kit offers a spa...

Страница 30: ... will require use of a TTC SIP configuration kit ordered separately see Accessories section Modules can be mounted on standard 35mm T Type DIN rail Input Input Reference Test Conditions 5 0V Square Wave Input Threshold Bipolar 0 0V Hysteresis 28mV Measurement Frequency Pull Up Down Disabled Cutoff Frequency 0 5Hz Samples to Average 1 Debounce 0ms Output Range 4 20mA into 250Ω load I O Scaling 0Hz ...

Страница 31: ...epending on the input frequency The technique used for measuring 0Hz up to 25000Hz results in decreased internal resolution with increasing frequency A 5000Hz hysteresis from 20000Hz to 25000Hz is used when switching sampling algorithms The technique used for measuring frequencies at or above 20000Hz has a constant internal resolution which is determined by the software configured Output Update ti...

Страница 32: ... selectable over the full input range 0Hz to 100000Hz Input Zero and Full Scale selections will be mapped to the output zero and full scale 100 current or voltage endpoints according to output range selected Configuration supports normal or reverse acting operation i e Input 0Hz to 2000Hz or Input 2000Hz to 0Hz Zero Scale Adjust Adjustable over 0 to 90 of Full Scale Input Full Scale Adjust Adjusta...

Страница 33: ...703uV 0 001598 0 to 10V 1 part in 59293 168 362uV 0 001684 5V to 5V 1 part in 31278 319 714uV 0 003197 0 to 5V 1 part in 60414 82 7623uV 0 001655 20mA 1 part in 62400 0 64103uA 0 001603 0 to 20mA 1 part in 58732 0 34053uA 0 001703 4mA to 20mA 1 part in 46984 0 34054uA 0 002128 Output Load Voltage output can drive loads down to 1000Ω minimum Current output can drive 21mA DC into 525Ω maximum Note H...

Страница 34: ...1 full speed only at 12Mbps Up to 32K commands per second USB 2 0 compatible NOTE Transmitter can not service USB interrupts when the input signal frequency is greater than 124KHz Input capture interrupts have priority over USB interrupts and will consequently override USB interrupts at such frequencies Transient Protection Transient voltage suppression on USB power and data lines USB Connector 5 ...

Страница 35: ... Environmental These limits represent the minimum requirements of the applicable standard but this product has typically been tested to comply with higher standards in some cases Operating Temperature 40 C to 80 C 40 F to 176 F Storage Temperature 40 C to 85 C 40 F to 185 F Relative Humidity 5 to 95 non condensing Isolation Input USB output and power circuits are all isolated from each other for c...

Страница 36: ...munity RFI per IEC 61000 4 3 3 Electrical Fast Transient Immunity EFT per IEC 61000 4 4 4 Surge Immunity per IEC 61000 4 5 5 Conducted RF Immunity CRFI per IEC 61000 4 6 Emissions per BS EN 61000 6 4 1 Enclosure Port per CISPR 16 2 Low Voltage AC Mains Port per CISPR 16 3 Telecom Network Port per CISPR 22 WARNING This is a Class A product In a domestic environment this product may cause radio inte...

Страница 37: ...ansient protection shall be provided that is set at a level not exceeding 140 of the peak rated voltage value at the supply terminals to the equipment Reliability Prediction MTBF Mean Time Between Failure MTBF in hours using MIL HDBK 217F FN2 Per MIL HDBK 217 Ground Benign Controlled GBGC Temperature MTBF Hours MTBF Years Failure Rate FIT 25 C 1 032 587 117 9 968 40 C 652 056 74 4 1 534 Configurat...

Страница 38: ...tion 29 JUL 2013 C JMO KLK Updated Diagnostics Table Updated Sensor Input Connections Table Updated USB Connections diagram 28 OCT 2013 D JMO KLK Added Duty Cycle Measurement Debounce and updated input specifications 12 NOV 2013 E JMO KLK Added MTBF Reliability Prediction 16 DEC 2013 F JEB ARP Removed P O Box from address 21 FEB 2014 G CAP ARP Added cULus Mark to this model removed pending 31 JUL ...

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