The basic flow is determined from a differential pressure sensor, this paticular application uses two sensors to improve sensitivity at the low end of the range;

• CH1 4-20mA measures 0-60mbar
• CH2 4-20mA measures 0-1300mbar
• When the pressure is below 52mbar (Con_a) then CH1 is used, when the pressure is above 57mbar (Con_a + Con_b) measured on CH1 then CH2 is used in the equation to determine flow.
  
  Where;
  • H = Measured pressure (mbars) measured from CH1 or CH2.
  • Q = flow
  • Z = a constant squared (we will recall the value of the constant squared from tables 3, 2 and 1 as it varies with pressure.

All calculated results are stored as follows;

• Mem9 stores the measured pressure used in the calculation.
• Mem4 stores the calculated flow
  
• Mem5 stores the calculated flow (mega litres per day)
• Mem6 stores total Mega Litres per day ML'. As calculation occurs every 500mS
  .

ML/Day Counter Reset

• When P1 (pulse input 1) is active the value in Mem6 is copied into Mem7 'ML last' to store previous count value and reset Mem6 to zero for a new count.

Hot Key Display

• Press 'UP' will display Mem4 'm3/hr'.
• Press 'DOWN will display Mem5 'ML/d'
• Press 'BACK' will display Mem6 'ML'.
• Press 'NEXT' will display Mem7 'ML last'
• Press 'UP' + 'DOWN' together will display 'CH1 mbar'.
• Press 'UP' + 'BACK' together will display 'CH2 mbar'.

Set Decimal Point on ACCESS Module

• Remove ACCESS MODULE from USC701.
• Adjust select switch to position 1.
• Fit ACCESS MODULE on USC701.
• Press 'BACK' to reduce decimal places (this application should have 0); press 'NEXT' to increase the number of decimal points.
• Remove ACCESS MODULE from USC701.
• Adjust select switch to position 0.
• Hot key display procedure above will now resume operation.

If unexpected results occur when loading the .usc file press back and click on help for instructions.

uap1063a.usc

First issue