Control return pump by means of flow-sensors

[APOUEY]

Hello
I want control my return pump (ROYAL EXCLUSIVE) by means of flow-sensors.
I do :


I plug "Interface Adapter for Red Dragon® 3 Speedy" to 1-10V-interface 1
I set "Constant flow = 1" function
I set "Nominal value =2000l/h" on flow-sensors 1



But I have the impression that the controller goes to 0% of the nominal value reached.

How to make the control of the proportional pump?

Thanks GHL