Problems with K8067

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1

Hi,

I use the K8067 sensor board. I made it because it’s for school (My end year). Now we have some problems. When we put 12 V+ like in the datasheet on the R11 we don’t see a change at the output. It looks like the LM335 don’t respond. We don’t know the problem. Is it also true , you have to not connect PIN3 of the LM385 ?

Regards Nicolas and sry for the language

2

The K8067 is a current loop sensor, you cannot measure a voltage change unless you correctly terminate the output with either 500 or 250 ohm, as indicated in the manual.
LM385 is a two pin device.

3

So i’ve i’m right , we can’t see a voltage change at the output ? How can we know i’ve our print is working ? we get 10 V at the output i’ve we put 12.7 V at the input.

Regards

4

Please read my previous post AND please read the manual of this kit !

You must terminate the output of the kit with either 250 ohm or 500 ohm. The resistors are supplied with the kit. Measure over the resistors.

5

[quote=“VEL417”]The K8067 is a current loop sensor, you cannot measure a voltage change unless you correctly terminate the output with either 500 or 250 ohm, as indicated in the manual.
LM385 is a two pin device.[/quote]

Hi,

I measure a light voltage change at the output when i put 12.7 V at the input. The change goes from 0mV to approximately 0.500mV , is this normal ? And a final question . Our LM335 is connected with a potentiometer but does this potentio have to give 0 our 5V to the LM335 ?

Grtz

P.S IC is not TLV274 but TL024CN (also good ?)

6

This is not correct.
Did you terminate the output with either 250 ohm or 500 ohm ?
Are you sure you did not mix up the sensor and the reference diode ?
If the IC is the original supplied with the kit, then it should be OK.

We suggest you return your kit for inspection.
Please return it to:

Velleman Kit Repair Dept.
Legen Heirweg 33
9890 Gavere
Belgium

7

Turn potmeter on K8055 until you get max. reading (255) using test software. Next, remove the jumper and connect K8063 WITH correct termination resistor or sensor. The K8063 is a CURRENT loop sensor, so you must mount the 250 or 500 ohm resistor, depending on the desired output voltage, as indicated in the manual.