The REG system devices require a 12 Vdc power supply and a BUS connection, therefore a total of 4 wires. The REG bus uses the EIA-485 standard (formerly known as RS-485), so the first choice is to use cables specifically created for this type of bus.
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BELDEN, 9841 (see https://www.belden.com/products/Cable/Electronic-Wire-Cable/RS-485-Cable)
CEAM, CPR 6003
TASKER, C521
FANTON, ACS 9841
Note
These models are given as examples of cables that have the suitable electrical characteristics; the electrical designer will have to verify the compliance of the chosen cable with the specific needs of the system: type of installation, fire resistance, etc.; BELDEN in particular has a whole family of EIA-485 cables, suitable for any type of installation).
The use of this type of cable and compliance with the "IN-OUT" wiring is MANDATORY as shown in the following image:PHOTO TBD
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Furthermore, it is important to underline that:
the devices order (REG-DIN-8/REG-EXP-8/REG-TH etc.) is NOT important, they must not be connected in any particular order
each device must be addressed and there cannot be two components with the same address
if the address is changed using a dip switch to any of the components, the power supply must be switch OFF and then ON again for the new address to be acquired
being the MASTER, REG-DIN-8 has no address
the 12 Vdc power cable and the bus cable (A and B) must NOT share the electrical conduits with the 230 Vac
Attention
if a cable is actually used as indicated, the shielding (in the following drawing highlighted in blue) must be connected ONLY IN ONE POINT to the zero of the power supply and where the cable is interrupted, to allow the connection of the various devices (in the example below a REG-DIN-8, a REG-EXP-8, a REG-THL sensor and a REG-OTG), the shielding must be spliced, but NOT connected to anything:
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The BUS cable that connects the devices (master, I/O expansions, combined temperature and humidity sensors, displays) as mentioned before MUST be wired "in/out"; do not create backbones or star connections:
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if the installation needs do not allow for in-out wiring (houses on several floors for example) it is possible to install signal repeaters/splitters (code RIP-RS485) which allow the bus to be split correctly:
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The BUS cable must NOT be closed in a loop, it must ALWAYS be OPEN!
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some very large systems may require multiple power supplies, in these cases the references (zero) of all the 12 Vdc power supplies of the regulation system must be short-circuited:
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Note
The choice to have multiple power supplies may depend on:
by the fact that there are so many components of the system that a single power supply could not support them all
dal fatto che i componenti (pure non essendo molti) sono molto distanti e quindi la caduta di tensione lungo la linea è tale per cui bisogna mettere un secondo alimentatore all’altro capo
da entrambe le precedenti situazioni
Per quanto riguarda invece le dimensioni dei cavi per l’alimentazione:
Il dimensionamento dipende da come i vari elementi sono distribuiti lungo il bus, e quindi linee guida generali sono impossibili da dare
Infatti il problema non è la capacità dell’alimentatore, quasi sempre sovrabbondante, ma la caduta di tensione lungo la linea
Assumere il caso peggiore (tipo che tutta la corrente, 5A per il PS60 ad esempio, sia assorbita alla fine della linea, diciamo anche solo 30 metri) porta a situazioni irrealistiche, con cavi con sezioni assurdamente grandi
Se si vogliono dare delle indicazioni di massima ad esempio per un appartamento/piccola abitazione dove le espansioni e il master sono vicini e all’interno del quadro con il loro alimentatore e lungo la linea per l’appartamento ci sono solo sensori e display, si può considerare un’alimentazione da 2x1 mmq fino a 50 metri.
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by the fact that the components (even though they are not many) are very distant and therefore the voltage drop along the line is such that it is necessary to put a second power supply at the other end
from both previous situations
As regards the dimensions of the power cables:
The sizing depends on how the various elements are distributed along the bus, and therefore it is impossible to give general guidelines
Indeed, the problem is not the capacity of the power supply, which is almost always overabundant, but the voltage drop along the line
Assuming the worst case (such as that all the current, 5A for the PS60 for example, is absorbed at the end of the line, say even just 30 meters) leads to unrealistic situations, with cables with too large sections
If you want to give general indications for example for an apartment/small house where the expansions and the master are close and inside the electrical box with their power supply and along the bus line in the apartment there are only sensors and displays, you can consider a power supply cables from 2x1 mmq up to 50 meters.
For different situations (very large homes on several floors, expansions spread across different electrical box) it would always be advisable to have this part sized by a qualified designer, who takes into account where the various devices are located along the line and how much each one absorbs.
BUS ERRORS TROUBLESHOOTING
Bus errors refer to lack of communication between the components of the REG system and if they occur the Bus Err led on the Master is ON and fixed. Before continuing with what is indicated below, check that the bus wiring has been done as indicated in the previous part.
If communication is restored, the Err Bus led disappears if you press the Reset button from RegConfig (Configuration Page 1) or from the REG display, press the OK button in the menu Information – Alarms/Bus Error – Address Bus Error until the error does not return to zero. Alternatively, power OFF and ON the REG-DIN-8.
When a fixed bus error occurs:
Check the wiring and the power supply of the device (below 9 Vdc the components may not be able to support communication via bus)
Try to reverse A and B
Check that A and B are not shorted
Check that the address of the component is correct. If you change it, remember to turn the power off and on again otherwise it will not be acquired
Check that you have also configured the correct address on the REG
Verify that all project components are present, installed and powered ON
Exchange the component with another working one
If the component works at this point, the problem is the bus wiring
Otherwise the component can be damage (check points 4 and 5 again)
The best test is to connect the component that does not communicate with a master external to the system and check its operation.
Interference presence (flashing/intermittent bus error)
On some systems, sporadic bus errors may occur on a certain number of rotating components. In this case, to resolve it, it is advisable to insert the 3 k Ohm or 4 kOhm polarization resistors between – and A and between + and B on the master (in the REG-DIN-8 batches from 22170 of July 2022 onwards the resistors are on board the PCB).
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In these cases, the bus, if not engaged in communication, could be positioned at an undefined voltage (floating) and this condition could lead to the slaves not identifying the start bit sent by the master. Then the slave misses the transmission and does not respond.