--[[
 these vars will be assigned only once
 global var will keep their values between scans
 BUT NOT between project restarts!!! -- for saving data between project restarts use D or DSxxx registers  or key-value storage
--]]
first_scan = true -- first scan flag 
GLOBAL_CONSTANT_1 = 100 -- UPPER case preferrable for constants

local now1 = 0 -- global because outside scope of main 

function main (userId)
      
  now2 = 0 -- also global because no "local" before 
         
  if first_scan then 
      first_scan = false 
      -- some actions only made once upon project restart
  end 
  
  now1 = os.time () -- get time from Lua function 
  now2 = GetReg ( "systemTime" ) -- get time form register with "systemTime" alias 
              
  if (now1 == now2) then 
      DEBUG ( "both time are equal" )
  else 
      ERROR ( "something wrong with time ... " )
  end 
end -- main