MM8 - How is CANbus Wired

MM8 - How is CANbus wired

MultiMon MM8 communication uses CANbus to communicate to the WatchMonPlus (WM5).  Twisted pair wiring is used to connect the devices.

CANbus is wired from the WatchMonPlus (WM5) to the first MM8, then onto the second MM8  and so on, to form a chain.  

Designating the End of the CANbus Chain

The last MM8 in the chain requires a 120 Ohm resister between CAN high and CAN low to indicate one end of the chain.  The other end of the chain could be the WatchMonPlus (WM5)  if there is no CAN link to an Inverter/Charger present or the Inverter/Charger itself.   

If using an Inverter/Charger, this is normally inbuilt into the device.  Where the WatchMonPlus (WM5) is one end of the chain it too requires a 120 Ohm resister between CAN high and CAN low.

Uniquely identifying the devices for CANbus

The Hardware - Cellmon page and Hardware - Integration page need to be setup to 

CellMon page

CellMon Type:  WatchMonPlus WM5 or MultiMon MM8 depending on device you are configuring.

Has Satellite:  On for the WatchMonPlus (WM5) and Off for any MultiMon 8's

Cell Identification: First Cell/Last Cell:  

  • Group Range is the numbers for the cell monitors on the device e.g. for example the WM5 may be 1-14.  For the MM8 the next number in sequence is chosen so if WM5 is 1-14 the first MM8 would be 15-28, the second MM8 would be 29-42 and so on.
  • Entire Range for the WatchMonPlus (WM5) should be the total number of cell monitors used so for example if two MM8 are used as suggested above then it would be 1 to 42.  For each of the MM8 the Entire Range should be identical to the Group Range.
  • Dif Nominal and Nom Series are used identically to normal multistring Higher Voltage systems would have a higher Nom Series, e.g. 28 below indicates 28s or a 96V nominal system.

Integration Page

CANbus Protocol choose as above.  Use Native 2 if not connecting to an inverter via CANbus

Base address identifies the cell monitors so 0 x 0520 for the WatchMonPlus (WM5), 0 x 0540 for the first MM8 etc.  Each consecutive one in the sequence should be allocated the next number 0560 0580 etc.

Remote address comes from the inverter.

Group address identifies the Master controller or those aspects of the MM8.

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