Octo Pulse and 0-10V control

[themindfields]

Hi guys! Yesterday I built very simple circuit to test my Octo Pulse 4 control capabilities. It consist of ESP32 for PWM signal generating and controlling it via WIFI, and PWM to 0-10 voltage converter module.

I was expecting gently and smooth ramp up of my octo pulse 4 flow rate, like on a graph below.

Unfortunately, to my amazement, it seems like 0-10V signal can only be used to switch between pre-build flow rate levels. When I run 10s voltage sweep through controller it was very visible on controller led indicators that it changes flow rate stepwise. Moreover, I couldn't spot any difference of flow rate when I was changing voltage within same pre-defined level, shown by controller. So let's say changing voltage from 1V to 2V didn't affect flow rate, until it reached 2.1V and jumped to next flow rate level on the controller. It disappoints me 'cause I hoped I will be able to create nice and gently sweep or even dial the flow rate down, compared to the lowest possible setting, using very small voltage :/

Now I have two questions for you guys:
1. For other octo pulse users who use 0-10V control from Apex or something else. Do you have similar observations? Or maybe I missed something? Does your controller behaves same, so flow rate is indicated on the 8 steps led indicator? In a manual it stands "When using 0-10V to control DC Pump, flow rate will not be indicated on the 8 Steps Flow Rate Indicator", so I'm not sure, because for me it is indicated...

2. How about other popular pumps with 0-10V control, like Tunze. I'm planning to sell my octo pulse 4s and buy 2x Tunze 6095 instead. Will I be able to create continuous sweep using 0-10V?

 

[Coolcasino]

On my VarioS pump controled via Apex... I cannot control the pump via its controller once Apex has control of it. Controller lights up but I connot control the speed.

 

[radiata]

My four Octo Pulse 4s are controlled my a Hydros. I haven't noticed any such "stepping" with them...