Device with Missing command Writtent Instruction?

[skdubey]

Hey Guys, 

I am using the gas flow-meter for my measurement and would like to get that reading on my lab-view program.

but there is no command instruction to read the data from the device. In such cases, how should one can proceed?

If it is showing the analog signal, How one can measure it and read in lab-view?  I am using RS232 cable for the reading the signal. 

Some details about the device:

a. OUTPUT SIGNALS: Linear 0-5 VDC (1000 Ω minimum load impedance) and 4-20 mA
(0-500 Ω loop resistance); 20 mV peak to peak max noise.

b. TRANSDUCER INPUT POWER: +12 VDC, 200 mA maximum; +24 VDC optional.
Power input is protected by a 750mA M (medium time-lag) resettable fuse, and a rectifier
diode for polarity protection.

[cbutcher]

If you're actually using RS232, you need to send some command and receive some response.

If the device actually only outputs those two signal types, then you probably want to instead use an Analog Input device to measure a 0-5V value (and scale appropriately, probably using some form of y=mx+c, where c might be 0...).

[skdubey]

I came to know from the manufacturer its "In regard to your inquiry, the FMA1700A/1800A mass flow meter has both a 0 to 5 voltage and 4 to 20 mA output available and it is a choice that customers decide to use.  There is no command provide with these flow meters".  I read that we need the DAQ device in order to convert the analog signal to the digital signal. Is this correct and the only way to do it? and second thing if I have 9pin MALE VGA connection. Which kind of DAQ I can buy? Is there any small DAQ available that will help me. Any other suggestions will help too. 

[GerdW]

Hi skdubey,

I read that we need the DAQ device in order to convert the analog signal to the digital signal. Is this correct

Yes.

and the only way to do it?

Yes.

if I have 9pin MALE VGA connection.

That is just a plug/port. Use a suitable connector (probably D-Sub9).

Which kind of DAQ I can buy?

Call your local NI sales support. (It will probably recommend a cheap USB600x-device.)

Is there any small DAQ available that will help me.

You can alos use some Arduinos…

[Bob_Schor]

We're doing this (water flow meter, also has voltage + current loop, we are using current loop, measuring voltage drop across a 1% 500 ohm resistor to Analog Ground of a NI USB-6001.  Works really well, and using current loop means we can also detect when a channel is not connected (will read 0 V, while connected channel with no flow will read 2 V).

Bob Schor

[skdubey · Accepted solution]

Solution: If anyone counter similar issue. 

In my case manufacturer couldn't able to provide the command instruction. As well there is no analog output on the device. It has DB9 Male VGA pins on the device. In order to resolve the issue my project manager suggested to connect wire to DB9 pins through wires. We shoulder the DB9 Pins with the wire and then connected this wire(voltage +ve and -ve inour case it was pin 2 and 3. Please check block diagram)   and later on to NI-PXI6341 and then to PXIe-8840 (I call it DAQ) . Then you can easily follow analog to digital footstep in the book "Hands-On Introduction to LabVIEW for Scientists and Engineers Paperback"  (DAQ Chapter). Voila it works.