====== Elreha cooling controllers ======

{{ network:vpr_19000_and_logo.png?direct&300|}}

The VPR-19000 Controllers for Compressor Compounds, Condenser Fans together with TAR/MSR/SMP refrigeration controller has been popular cooling solution and can be found in many large food malls or supermarkets. 
There is an obsolete software tool for WinXP to monitor the system, which can show a tree of the controllers network and show/modify their parameters using tables.

With the WebHMI visualization, alerting and analytics capabilites, you can greatly empower your refrigeration monitoring system. The controllers can be read using [[custom_protocols?s[]=custom]]

Turn to your local representative for more information. 

<code lua - example.lua>
SOH = 0x01
STX = 0x02
ETX = 0x03
EOT = 0x04

LIMIT_BYTE_COUNT = 255

CACHE_REFRESH_DELAY = 5 * 60 

function readRegister (reg, device, unitId)
    
   local iAddrString= tostring(reg.internalAddr)
   local targetBase = tonumber(string.sub(iAddrString, 1, (#iAddrString - 1)))
   local targetOffset = tonumber(string.sub(iAddrString, -1))
   
   if replies[targetBase] then 
       ERROR('there is entry for targetBase!')
       local ifData = replies[targetBase][targetOffset]
       if ifData then 
            ERROR('there is an entry for page: ')
            tprint(ifData) 
            return ifData['data']
       end 
        
   end 
   
   
--   ERROR('Target base and offsets ' .. targetBase .. ' ' .. targetOffset)
   
   if syncRequest() then 
       local packet = finishRequest()
       
       if packet then 
           local b, o = parseRequest(packet)
           b = tonumber(b) ; o = tonumber(o)
           
           if (b and o) then 
               if (not readUntil(string.byte('#'))) then 
                  return false 
               else 
                  
                  local replyAddr = tonumber(readString(4))
                  
                  if (replyAddr == b) then 
                        
                        ERROR('reply address equals requst addr = ' .. replyAddr)
                     local data = readUntil(ETX) 

                                                -- DATA PROCESSING 
                     if not data then  
                         ERROR('Could not read data in response ((( ') 
                         return false 
                     else                      
                         
                            -- get string presentation 
                         local dataAsString = {}
                             for i, v in ipairs(data) do 
                                dataAsString[i] = string.char(v) 
                             end 
                         data = table.concat(dataAsString) 
                        --  ERROR(data)  
                            
                            -- check if data in cache 
                         if (not replies[b]) then 
                             replies[b] = {} ;      ERROR('Entry for the ' .. b .. 'device was created!')-- create entry for DEVICE 
                         end 
                            -- if sub-set in the group 
                         if (not replies[b][o]) then 
                             replies[b][o] = {} 
                             replies[b][o]['data'] = data ; ERROR('Entry for the data in ' .. b .. ' ' .. o ..  'was created!')-- create entry for data 
                             replies[b][o]['stamp'] = now 
                             
                             ERROR('Now data in cache = ' .. replies[b][o]['data']) 
                         end      
                          -- check if data is old or no 
                         if ((now - replies[b][o]['stamp']) > CACHE_REFRESH_DELAY) then 
                             replies[b][o] = nil          ; ERROR("Killed data in " .. b .. ' ' .. o ..  'after timeout!')
                         end 
                         
                         
                         ERROR('types of targetBase, targetOffset, b, o')
                         ERROR(type(targetBase) .. ' ' .. type(targetOffset) .. ' ' .. type(b) .. ' ' .. type(o))
                         ERROR('data in cache in this point ' .. replies[b][o]['data']) 
                         
                         if not replies[targetBase] or not replies[targetOffset] then 
                             ERROR('No data in cache for ' ..  targetBase .. ' '  .. targetOffset)     
                             return false 
                         else 
                             return replies[targetBase][targetOffset]['data']
                         end 
                         return 1 
                      end 
                  else 
                      ERROR('reply address does not equal requst addr = ' .. replyAddr .. ' ' .. b)
                      return false         
                  end 
               end 
           
           else 
               ERROR('Wrong base offset from parseRequest!')
               return false 
           end 
       else 
           return false 
       end 
   else 
       return false 
   end 
   
end -- readRegister 

</code>