7.5
Control the pH
pH PID control loop
The pH PID control loop is a split range loop: the output of the pH control loop controls
both the acid and base pump PID control loops. The acid and base PID control loops are
nested loops inside the pH control loop. The error of the outer loop (pH control loop)
controls the CVs of the inner loops (acid and base control loops).
The pH control can be set to work in Auto or in Manual mode. In Auto mode, the PLC
controls the pH of the disposable bag contents to the setpoint (SP). In Manual mode, the
PLC keeps the pump speed at the manually defined CV value (% of total pump speed
range). See
Work in Manual mode, on page 223
for more information.
Work in Auto mode
To set the pH control to work in Auto mode follow the instructions below.
Action
Step
On the home screen, tap pH/Cond to open the pH and conductivity overview
screen.
1
Tap pH on the pH and conductivity overview screen to open the pH Detail
screen.
2
On the pH Detail screen, press the Probe 1/Probe 2 button (1) to select the
correct probe.
3
1
2
Make sure that the instrument is in Auto mode (2). If the Manual button is
shown, tap the button to set the pH control to Auto mode.
4
Xcellerex XDUO 2500 Mixer Operating Instructions 29146667 AH
221
7 Operation
7.5 Control the pH
