Range Migration Faliure Analysis of Differential Pressure Transmitter

When choosing our differential pressure transmitters like UPB5, below information can be help to analyze the migration fault. 

1. Positive migration fault: 

1.1 Close the positive and negative pressure measurement chambers of the valve group, open the balance valve and the instrument venting plug. 

At this time, the instrument output should be lower than 4mA. 

If the output is not lower than 4mA, it may be that the lead of the positive pressure chamber or the three-valve group is somewhat blocked. 

1.2 Next, close the pressure point of the positive pressure chamber, open the open-air switch, and the output should be 4mA at this time. 

If the output is lower than 4mA, it may be that the migration amount is small or the zero position is low; if the spacer fluid is filled, it may be that the spacer liquid is not filled or leaked from the side; 

If the output is higher than 4mA, it means that the migration amount is larger or the zero position On the high side. 

2. Negative migration fault: 

2.1 Close the positive and negative pressure measurement rooms of the three-valve group of the differential pressure transmitter, and open the balance valve and the instrument venting plug, the meter output should be 20mA. 

2.2 Secondly, close the pressure points of the positive and negative pressure chambers, and open the open-air switch. 

At this time, the output of the instrument should be 4mA. 

If it is not 20mA or 4mA, check whether the leads of the positive and negative pressure chambers are blocked, whether the migration amount has changed and the zero position is accurate, whether the isolation fluid is lost, etc.

For more details, please contact Stella Meng.