Omega Engineering DP3600 사용자 설명서

 

12 

PROCESS CHANGE 

 

 
The system will constantly monitor  the total amount of change in process variable since start or last reset. 
This change is displayable in engineering units by pushing the ‘PR CNG’ key. 
 
This function is useful in tracking the change that has taken place in the process e.g. in a tank containing 
300 gallons of water, an addition of 200 gallons will show that the total amount of water is 500 gallons. On 
pushing the ‘PR CNG’ key the display will indicate 200 gallons as the total change. Now assume that 400 
gallons of water is pumped out. The total amount of water left in the tank would now be indicated as 100 
gallons. The change that has taken place in the total volume of water from its original 300 gallons can be 
displayed by pushing the "PR CNG" key and it would be 200 gallons. 
 

 
To start tracking the change from a new point, the Process change being indicated can be reset to zero . To 
do so, push the ‘PR CNG’ key twice and keep it pushed. The display will flash the present change value 
three times and then reset it to zero (keep the "PR CNG" key pushed till the display shows zero or close to 
zero). This flashing feature is provided so that if   ‘PR CNG’  key gets pushed twice accidently while trying 
to display the process change it would provide a chance to get out of reset mode without actually resetting 
the reading. Therefore, if  ‘PR CNG’   key is released any time before the three flashes, the current reading 
of "Process Change" will be retained. 
 

SCALING 

 
Scaling is useful in reading the sensor output directly in engineering units e.g. a load cell putting out 4 - 20 
ma signal can be scaled to read 0 - 4000 pounds of load. 
 
Scale  is entered as two different values i.e. High Scale and low Scale. High scale corresponds to the 
maximum output of the transducer and low scale to low output. e.g. For a 0-5V transducer if it is desired to 
read 200 units at 0VDC and 3000 units at 5VDC output then set low scale equal to 200 and high scale to 
3000. The DP3600 unit will linearly scale the transducer output. For a transducer with 4-20ma the low scale 
reading can be obtained at the programmed offset value. For instance if offset is set to 4.00, then the low 
scale reading will be obtained when the unit sees a 4.00ma signal from the transducer.  
 
Scaling is obtained during setup mode and immediately follows the setting up of decimal point. Maximum 
programmable high scale is from 1-30000 and low scale from 0-high scale value.  
 
Scaling can be programmed and displayed in SETUP mode only (look under setup). 
 
 

OFFSET 

 
The system provides the capability of programmable offset. This is useful if a certain amount of input from 
the transducer is required to read zero e.g. for a 4-20ma input , 4ma can  be made to read zero. 
 
Offset can be programmed and displayed in the SETUP mode only (look under setup).