CP1L, TPO for valve regulation

[p001p 0]

So, hello all. I'm new in Omron PLC.
Using: CP1L-EM controll + CP1W-TS102 (x3)
Problem: I need to regulate the valve with motor drive. You can meet the same in heating system for control the temperature of water. Logic is simple, 
- low temperature? - open valve step-by-step
- high temperature? - close the value step-by-step

I always use PWM regulation, but in Omron PWM only for encoder (srsly, i don't need 10k impulses during short period of time, i need just several impulses during the time)
So, i decided to use TPO. The input calue for TPO is output value from PIDAT. (W451 manual, description of TPO function, example)

What's the problem? 
1. I need to make difference time between impulses. 
Look here:

I have 55 C temperature of the water, but i need 80 C, so i need impules for 8-10 sec duration, but when the temper close to 75-79 degress i need the impuls 1-2 sec duration. And, as i read, TPO cant do this, right? Just constant duration in 1 TPO instruction, or use several TPO instruction.

Other situation, i have 80 degree Celsius, but i need 50 C, so i need to close the valve. 
But i have only 1 TPO! So i need to check the difference beetwen SP (set point of temperature) and PV (process value) and if it hegative - go to PIDAT #1, which connected with TPO #1 and close the valve (SP-PV need to be around 0)

If i have positive value (SP-PV) i need to go to PIDAT #2 wich connected with TPO #2..... 

Srsly? I cant make the measure between -100 .... 100 for 1 TPO function and use 2 digital output? 

I know that 0...10v regulation is better, but i have that i have =)

 

Sincerely, p001p