RS485 substitutes...

[silentboarder69]

Hi,
I'm doing an installation of an air source heat pump system for a customer. In the specs, the user interface, heat pump and cylinder need a cable connecting each other. This is specced as RS485. My local supplier doesn't stock this, can I use 1.0mm 5 Core PVC Flex 3185Y?

Thanks in advance,

Rick

 

[Rockingit]

Er....confused. RS485 is a protocol, not a cable type. Are you sure you're reading the manual correctly?

 

[silentboarder69]

The required controller cable is a shielded MODBUS cable RS485, for example a 4 core 1mm² 24 AWG (Nominal impedance 120Ω) Foil and Braid, which can be purchased from Dimplex as an accessory.

 

[Rockingit]

RS-485 - Wikipedia, the free encyclopedia

 

[Rockingit]

The required controller cable is a shielded MODBUS cable RS485, for example a 4 core 1mm² 24 AWG (Nominal impedance 120Ω) Foil and Braid, which can be purchased from Dimplex as an accessory.

OK....what you need to install is a shielded data cable. RS485 works at very low voltages (>< 200mV) and at very high speeds. If the manufacturer is recommending a particular type, as above, then the easiest thing is to buy it (or find an exact equivalent on line and buy that much cheaper).

 

[Robotstar5]

Belden probably have something suitable - link

 

[Jimsparky]

Belden 9841. 1 * twisted pair.

 

[rmaynard]

I always use belden for communications on boiler and air handling systems

 

[Guitarist]

The required controller cable is a shielded MODBUS cable RS485, for example a 4 core 1mm² 24 AWG (Nominal impedance 120Ω) Foil and Braid, which can be purchased from Dimplex as an accessory.

Do that then.

 

[FAA Greenie]

My local supplier doesn't stock this, can I use 1.0mm 5 Core PVC Flex 3185Y?

Whatever you buy, don't use the above!!

As said above the 458 is a data cable, basically used for transmitting digital info from one device to another, or several others at high speed. These cables are impedance matched to the equipment they are linking (like Tv aerial cables do) so will have a higher impedance that 5 core flex.

In a nutshell, you need to find the right cable.....

 

[Tridentsystems]

Use Belden or similar. Although anything will work with shielding. Remember to only ground shielding at one end though