I’m considering the installation of a system for monitoring and control a thermal storage system in a solar collector field using Fieldpoint for measuring temperatures, fluid flow, pressures, etc. The instruments and equipment we want to control and monitor are more than 300 m apart from our main control room. I’m considering two possibilities to connect the PC dedicated to this task, one is the use of Fieldpoint network module FP-1601 (Ethernet) and the other is the module FP-1001 (RS-485). We would prefer to use FP-1601 but then the maximum Ethernet segment length is 100 m. I don’t know if it is possible to change from copper wiring to optic fibber using a medium converter, then the maximum length segment will be limited to 2 km or longer. Two medium converters will be necessary, one close to the PC and one close to the Ethernet network module. Other possibility it could be the use of a wireless LAN but I don’t know if it would be a better option and cheaper.
But related the module FP-1601 I’m worried about its operating temperature range (0 to 55ºC), whereas the FP-1001 has a similar range to I/O modules (-40 to 70ºC). For us, the operating temperature is something crucial because the hardware is going to be mounted in a solar field, inside cabinets and we are not sure if it’s recommendable or not the use of air conditioning for this hardware.
Could someone give me any inputs about these questions?
Thanks very much in advance.
You can use a media convertor to extend the minimum distance as you describe, you will need to watch things like bending radius on the fibres.
Anyway if you put a couple of hubs in you could get 300m using copper and ethernet.
device ----100m ---- hub ---- 100m ---- hub ---- 100m ----- router
Alternatively you could communicate over RS485 from the serial interface if the bandwidth will suffice.
Wireless lan is 300m free field in ideal conditions of antenna location, but the rate will likely drop to 1Mbs.
One thing to consider is near lightning strikes which with long cable runs could give rise to high voltages on copper. This will probably just retire things very early but could be dangerous if not managed carefully.
But what are you doing about power out in the field to power all this stuff and you will no doubt have to make all those connections water tight?
As far as temperature is concerned you will affect the reliability considerably if you exceed the stated limits, control cabinets typically get to 40°C, much over 50°C and you start looking at either specialist equipment or cooling of some form, from a fan to pletier devices or air conditioning units. Plastics start to become brittle and cables should be checked for operating temperature range from cold to hot. Things expand and contract a lot and you will need to manage any condensation. Look under the bonnet of an old car for what can happen and a new one for some good ideas on what you can get away with.
Is this the sort of input you were looking for?
Thanks very much for your inputs.
The system will be power from the control room. The connections are protected from water because there are distributing chutes along the solar field.
About the operating temperatures, we are considering the use of isolated cabinets (IP 55 or higher) equipped with air conditioning.