REC Master9M with new REC2Q Slave Units - Cable from Master to 1st Slave: which cable colour goes where

• 2Q
• BMS

• M

  Martin

  11/3/23, 12:18 PM

  A few weeks ago I received 1 REC Master 9M and 3 of the new REC2Q Slave units for a 12V 3 parallel bank installation directly from REC in Slovenia.

  They also included the RS485 cable from the Master9M to the 1st REC2Q slave.

  This cable has the female DB9-Sub plug on one end and 6 differently coloured cables with the pins already crimped to insert these pins at the RS485 in on the 1st slave at the pins 4,5,6,12,13,14 on the TE Connectivity 14pole plug (TE 749202-1).

   

  My problem is: No matter how often I read the available manuals (I know they are in revision due to the new REC2Q's) I can't find out which pin on the Master9M DB9-Sub carries which cable (RS485 Signal A, RS485 Signal B, GND, Shield, +5V and +5V BMS enable from Master).

  Anyhow I found out by measuring conductivity which pin on the DB9-Sub female goes to which cable colour:

  Pin 1: Black cable

  Pin 2: Gray cable

  Pin 3: Green cable

  Pin 4: Yellow cable

  Pin 5: not used

  Pin 6: Pink cable

  Pin 7: not used

  Pin 8: not used

  Pin 9: White cable

   

  But this doesn't help me as I still don't know the pinout on the Master9M DB9-Sub male.

  I already wrote Tine at REC directly and he sent me a reply. He wrote:

  "RS485 Communication:

  Master-Slave communication

  Master:

  DB9 Slave

  1 shield

  2 GND RS485

  3 B

  4 A

  6 RS485 5V power "

   

  So this are only 5 cables or pinouts but I have 6 cables on the other side.

  I'm interpreting this as if the white cable on pin 9 was missing in his pinout and this must be the cable for +5V BMS enable by Master in a Master-Slave configuration.

  Can anybody here confirm that my following assumption is right ?

  Maybe this will help also all other users who have the new Master-Slave combo....

  Assumption:

  Pin 1: Black cable = Shield

  Pin 2: Gray cable = GND

  Pin 3: Green cable = RS485 Signal B

  Pin 4: Yellow cable = RS485 Signal A

  Pin 6: Pink cable = +5V RS485

  Pin 9: White cable = +5V enable REC2Q Slave from Master

   

  Do you think my assumptions are correct ?

  Thank you everyone for your your help.

  Kind regards.

   

  Martin

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• R

  Rick OGM Support Staff

  11/4/23, 10:19 AM

  We did this sketch a while back for our customers.  Hope it helps

  

   

   

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• P

  PeterD

  10/31/24, 7:41 PM

  I'm in the process of working on this same wiring for one 9M master and two 2Q slaves. 

  While I did purchase the necessary cables, I still will need to insert the wire terminals into the 14-pin MNL housing. So the right half of that diagram is very helpful.

  That diagram above, which is also on page 4 of the document "REC-Series-Master-2Q-Slaves-Wiring-1-0-1.pdf", has an error in the pin numbering for the DB9 connector. Pins 6-9 are reversed; pin 6 should be at the bottom and pin 9 at the top, in the view shown. That view, BTW, is shown as looking at the mating face of the socket-pin plug, not the soldering side of it. Luckily, most DB9 connectors included numerals molded into the plastic insert!

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• P

  PeterD

  11/30/24, 8:27 PM

  FWIW, the later revision of the wiring diagram document, "REC-Series-Master-2Q-Slaves-Wiring-1-0-1-6.pdf" still has the pin numbering error on page 4 at the DB9 connector.

  Again, pin 6 is at the bottom (Pink +5v Out) and pin 9 is at the top (White +5V In).

  So the physical positions of the White and Pink wires are shown correctly; it's just the numbering (6, 7, 8, 9) that is backwards (should be 9, 8, 7, 6 from top to bottom).

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