OK , so after looking at pdf from yor original post and identifying component as Proline Promass 40E.
Here are links to documentation regarding device.
https://portal.endress.com/webapp/ProductContainerGUI/plain/downloads.jsp?root=40E&filter=010.040&lang=enhttps://portal.endress.com/wa001/dla/5000319/0459/000/06/TI00055DEN_1418.pdfSecond link is a datasheet for given flow meter. From there we can see that terminals 1 & 2 are your 120VAC connection.
Further on we can see that device has 4 different output options:
1) 4-20mA active (no extra power supply) current loop/supports HART protocol
(google Highway Addressable Remote Transducer Protocol) 2) 4-20mA passive current loop (need extra supply 18-30VDC)
3) Continous freqency output
4) Pulse output
All outputs are galvanicly isolated (that is a good thing) , most likely by using opto-copulers.
After reading datasheet , I have to say this is very capable device and there are many ways to implement this device in to a system.
That is why there are so many different outputs.
What you are asking about is system control implementation called Relay logic.
With that being said , YES , you can use this device to control valves , preassure regulators or any other simillar device.
You can achieve this by using HART protocol. By using valves and actuators that have build in HART (4-20mA loop) support.
Outputs 26 & 27 are ones that you are interested in.
Depending on a problem you are trying to solve you might be able to connect flow meter DIRECTLY to a preassure regulator or actuator , BUT also you may need to use PLC or a group of relays and/or timers to achieve proper regulation.
FOR MORE DIRECT ANSWER please , tell us exactly what do you wish to do.
Note also that in order to utilize HART protocol , device NEEDS to be configured.
From operation manual
https://portal.endress.com/wa001/dla/5000000/0371/000/02/BA062DEN_0908.pdf, we can see (page 5) that you need HART Communicator DXR 375 (stand alone unit)
or Commubox FXA193 modem for a PC in order to do that.