I'm sorry, i know i'm putting some ridiculous constraints and i could simplify this, but the pump model i received already has the controller attached, and P1-P4 came pre-connected to buttons, encoder and display. I'd prefer to leave them connected as an option to control the pump physically.
I'm a new user, so i can't upload pdfs, and downloading the spec sheets from Kamoer requires registration, so it would be an extra hassle for everybody else. The pump sheet says:
Control method
Rotary encoder, foot switch, external analog signal, 485 communication control
The controller configured for this product is our company's 2802 pulse generation control board. For functions and usage details, please refer to the "2802 Pulse Generation Control Board Manual".
And the board manual just has the images i pasted before (pdf won't let me copy text), safety precautions and a bunch of controls and settings using the buttons.
The only other relevant lines are
Simulated signal control mode
Control operation is carried out through analog signal method(0-5v, 4-20mA), please connect the signal line according to the actual control method.
which does not really help me with the wiring.
I'd really like to explore the simulated signal control mode.