K8047

Instruments PC Oscilloscopes and Recorders
1

Bonjour,

J’ai fait l’aquisition du datalogger K8047.

Quatre questions:

  1. La led rouge à l’enregistrement ne s’allume pas et la led verte s’est allumée un certain nombre de fois lors de la connexion USB mais par la suite ne s’est plus allumée.
    Sinon tous semble fonctionner correctement
    Avez-vous une idée du pourquoi ?

  2. Lors de l’enregistrement, même en prenant divers time/div 1sec, 5sec, … le logging sur plusieurs heures ne fonctionne pas.
    On dirait que que les points de mesures n’excedent pas 1700 comme le fichier de 1700 lignes qui est créé.
    Alors un enregistrement sur une longue période (plusieurs jours) est-il possible ?
    Si oui comment ?

  3. Quelle est l’intensité max sans risquer d’endommager le K8047 ?

  4. Je devrai également utiliser ce datalogger pour mesurer des tensions de l’ordre du millivolt, avec quel appareil puis-je amener cette tension (mV) à une tension de l’ordre de 3, 15 ou 30V ?
    Disposer de KIT qui pourraient remplir cette tâche ?

Merci pour les infos

2

I hope I understood your questions:

  1. After connecting the USB cable the green LED (labeled USB POWER) should lit continuously. The red LED (labeled RECORDING) should flash three times and then go off. If the green LED blinks several times there must be bad contact in the USB cable or bad soldering on the PCB.

  2. You can log the data for several hours (or weeks) even at the highest sample rate 100 samples/sec (selecting 1 sec/div range): Select from the File menu the option ”AutoSave Data”. Enter a file name and click ”Save”. Then just click the ”Run” button and the recording start. Recording stops when you next time click the ”Run” button. The data will be saved to file.

  3. The maximum specified voltage is 30 Vdc. If you look the circuit diagram you’ll see that there are 1M ohm resistors in series of each input. Those are there to protect the electronic circuit against overvoltage.

  4. The lowest voltge you can see on the screen is 10 mV. You have to build external amplifier to measure mV signals. It is easily done using an operational amplifier.

3

Hi,

Thank you for your answers.

For the question number 3,
the question was : What the max I (and not V) that the K8047 can accepted.

For the question 4,
You wrote “You have to build external amplifier to measure mV signals. It is easily done using an operational amplifier”.

Can you give me information to found this operational amplifier that could tranform milliVolt (1-10mV) to Volt (1-10V) ?

Sorry for my english
Thanks for your help

4

No problem. I understand now your question:
The input current at 30V input voltage is about 30uA.

You may use any Rail-To-Rail Input/Output op-amp to amplify the voltage.

You may use the K8047 circuit diagram as an example.
The selection of the TLV274 was based on two features:

  1. Common-mode input voltage range: 0V to VDD–1.35 V
  2. Rail-To-Rail Output

Please note that the max supply voltage for TLV274 is 16V.