RE: Motor Operated Valve. The head of the operator is often shown as M inside a square. The limit switches ZSC/ZSO is acceptable under ISA. I have never seen ZSH/ZSL (high and low for a linear valve I suspect) in my industry. If the valve is used for on/off, it usually takes a XV or UV tag name. If the valve is used for regulatory control application, then they would take the normal PV, FV, TV type of designation. I have also seen HV for operator control only valves.
To join the United States Marine Corps as an infantryman or, as that military occupational specialty is known in this branch of service, rifleman, you need a general technical score of 80 on the Armed Services Vocational Aptitude Battery.
To join as a regular soldier you need to be at least 16 years old, although you can start the application process earlier, with your parents' permission. If you're under 18, you'll also need parental consent to join. You should be in Army phase 1 training before your 33rd birthday. To apply to become a regular officer you need to be between 18 - 28 years and 11 months, although you can apply for sixth form and university sponsorship before you reach this age.