I am designing a data acquisition system including a sensor that outputs a TTL pulse signal (3 wires: power supply, common, and signal). I am trying to determine how to send this signal to a program like LabVIEW, and was wondering if an FTDI cable would be able to do this? If not, what should I look into in order to connect this sensor?

It is a Monarch Instruments Optical Tachometer, ROLS-W, data sheet here: http://monarchserver.com/Files/pdf/1071-4851-114_ROLS_Instruction_Sheet.pdf?1815445338784657948

  • \$\begingroup\$ what is the protocol that the signal uses? \$\endgroup\$ – jsotola Feb 12 '18 at 2:02
  • \$\begingroup\$ I'm sorry, I am new to data acquisition and don't understand what protocol means. The sensor requires a DC power input, and gives a positive pulse proportionate to the supply voltage. Does this answer the question at all? \$\endgroup\$ – kmar13 Feb 12 '18 at 2:14
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    \$\begingroup\$ communication protocol is a specification of how the voltage on the wire changes with time in order to convey data from one place to another. ... if the sensor uses RS232 then the FTDI cable may work. ... what is the sensor that you are trying to connect (part number, web page). \$\endgroup\$ – jsotola Feb 12 '18 at 2:21
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    \$\begingroup\$ Maybe you just tell us what "a sensor" is, and we can figure out (explain) what is the best for you? \$\endgroup\$ – Ale..chenski Feb 12 '18 at 2:39
  • \$\begingroup\$ With LabView you choose a low cost interface board of your choice. On that accepts RS-232 would be fine. Since you write the software in LabView, you set the protocol. Look up 'Modbus' for a simple hexadecimal based protocol. \$\endgroup\$ – Sparky256 Feb 12 '18 at 3:10

Your question is lacking specifics about the pulse's properties—e.g., pulse width (min,max); time interval between pulses (min,max), etc.

However, since you specifically mentioned National Instruments (NI) 'LabVIEW' software, NI and other companies sell data acquisition (DAQ) devices that are specifically designed for use with LabVIEW. Some of these DAQ devices are lower-cost, USB-based devices that you plug in to an available USB port on a computer that is running LabVIEW. You simply connect your TTL signal to one of the DAQ device's digital input pins, and then write a LabVIEW program (a.k.a., a "virtual instrument" or simply "VI") that monitors that digital input pin on the DAQ device. In other words, there's no need to create your own DAQ device when you can purchase a DAQ device that is specifically designed for use with LabVIEW. (n.b. This is not intended as a recommendation for, or endorsement of National Instruments or its products. In the interest of full disclosure, I sometimes use NI's LabVIEW software and DAQ devices.)

Additionally, there are free software libraries you can download that enable communication between LabVIEW and embedded computer boards like Arduino, Raspberry Pi, BeagleBone Black, etc. With these libraries you can, for example, create a basic data acquisition system around an Arduino board, and use a LabVIEW program to communicate with and control that Arduino board via a USB cable—e.g., to trigger data capture on the Arduino; to offload captured data from the Arduino to the LabVIEW program, etc. Two examples of these free software libraries for LabVIEW are:

  • National Instruments' LabVIEW Interface for Arduino Toolkit
  • MakerHub LINX for LabVIEW

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