Choosing LOGO outputs for heating device

Hello,

I want to choose the right Logo plc with correct outputs for controlling heating devices like 3 point mixing valves. As I understand it would be a mistake to choose Logo with relay outputs, because controlling 3 point mixing valve requires a lot on-off cycles during operation and relays will fail after short time of period (or maybe this period is not so short?). Instead I should select Logo with transistor outputs and connect to them coupling relays? How about when I can sense 220Vac inputs with proper protection to plc? Can I also use coupling relays with 220Vac coils and connect 24Vdc to output terminals and provide to plc input?

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Split from Transistor outputs, Relay outputs difference.

Thank you ixo65 for your answer. I know that better solution it would be using proportional valves and control them with analog outputs. Still some environments are already equipment with 3 point mixing valves. I have no experience on selecting appropriate relays. Just google internet and found for example some relays:

https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=2903342&library=usen&pcck=P-16-06-02-01&tab=1   and 

https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=2903339&library=usen&pcck=P-16-06-02-01&tab=1

Are these relays suitable for interfacing Logo?

The second relay is with 220Vac coil. I have also some 220Vac signals/sensors and I need to provide input to LOGO. In this case I connect relay input coil to 220Vac, one relay output contact to +24Vdc power, second contact to LOGO input. Is this a proper way to do so? Maybe I can damage Logo inputs if some voltage peak comes from 220Vac supply line?

The way in which you want to bring 220VAC signals by coupling relays to the logo is right.

The inputs of 24VDC Logo tolerated no 220VAC, it can be destroyed.