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:
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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.
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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
Verificare che l’indirizzo del componente sia corretto, se lo si cambia ricordarsi di togliere e ridare corrente altrimenti non viene acquisito
Verificare di aver configurato l’indirizzo corretto anche sul REG
Verificare che tutti i componenti del progetto siano presenti, installati e alimentati
Scambiare il componente con un altro funzionante
Se il componente a questo punto funziona il problema è il cablaggio
Altrimenti resta il componente (verificare nuovamente punti 4 e 5)
La prova migliore resta quella di collegare il componente che non comunica con un master esterno al sistema e verificarne il funzionamento.
Presenza di interferenze (errore bus lampeggiante/intermittente)
Su alcuni impianti potrebbero verificarsi errori bus sporadici su un tot di componenti a rotazione, in questo caso per risolvere si consiglia di inserire le resistenze di polarizzazione da 3 k Ohm o 4 kOhm tra – ed A e tra + e B solo ad uno dei due estremi del bus (nel lotti di REG-DIN-8 dal 22170 di luglio 2022 in poi le resistenza sono a bordo PCB).
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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.