Digital panel meter problem

[mohsen 2012]

Hello , i buy a small digital panel meter PM-438 , i want to use it in my power supply to measure voltage ,
i configure it to measure 200 V :






The problem is that the meter did not show the input voltage , it always show '' 1 '' in the lcd !!!


I turn the variable resistor but the lcd show the same value : '' 1 '' !!!
Here the datasheet of the meter :
https://www.hestore.hu/files/pm438.pdf
please help me and thanks.

 

[d123]

Hi,

The pdf says 10Mohm and 1Kohm and no jumper to measure voltages over 200V. I think you said you are using 10k, but need to use 1k in its place.

If the input range is only 199.99mV, that would greatly explain the "1" appearing, as 10000/1010000 = 0.0099,

...220V * 0.0099 = 2.17V... a lot higher than the 200mV range.

However, from the photo the "10k" looks as though it has a red stripe where it should be orange, in which case best check the 10Mohm is correct at the same time as verifying the 1 or 10k.

 

[mohsen 2012]

Hi,

The pdf says 10Mohm and 1Kohm and no jumper to measure voltages over 200V. I think you said you are using 10k, but need to use 1k in its place.

If the input range is only 199.99mV, that would greatly explain the "1" appearing, as 10000/1010000 = 0.0099,

...220V * 0.0099 = 2.17V... a lot higher than the 200mV range.

However, from the photo the "10k" looks as though it has a red stripe where it should be orange, in which case best check the 10Mohm is correct at the same time as verifying the 1 or 10k.

Thank's sir , i have solve the problem by changing RB and RA , i put RB resistor in the place of RA and the RA in RB place and the meter is work great :


i test it with a '' died '' 9v battery
Before the resistor the third strip is red but its value is 10K.!!.