Troubleshooting At Can Bus Faults - Intec MLC 8000 Operating Manual

INTEC GmbH
Lift controller MLC 8000
22/12/2016
Operating manual V2.0

4.10 Troubleshooting at CAN bus faults

The fault diagnosis by the lift controller only works as long as the CAN bus connection
between the individual control modules works.
Even if errors in the data transmission are displayed in the error stack of the controller, the
reason can only be found through a systematic approach.
At this point once again it has to be pointed out that the lift controller has 2 separate CAN
bus systems:
- Control bus
- Shaft bus
In addition, some drives can also be connected via the RS485 bus (only if main board MCU
is used).
For group of lifts (in some cases also single lifts with large hoisting height or large floor
number), the shaft bus can be divided into individual branches by the bus coupler (CBK). In
this case, the shaft bus is physically divided into different segments, but logically, it is for the
lift controller still 1 shaft bus system.
If the data transfer on a CAN bus is totally disturbed, then the error "Bus off" appears. In this
case, even the hand-held terminal can no longer be used to diagnose problems, but it is still
possible to work with the keyboard and the LCD display on the HSE.
If a data transfer is possible, but some individual modules like FVE, TSE or ESE are missing,
the CAN bus connection can be checked by hardware test menu.
If an assembly does not appear here, then it can have different causes:
- The corresponding module is defective
- The bus cable to this module is not connected correctly
- The node number of the module is not set correctly
If the data traffic on the CAN bus is totally disturbed, then the following procedure is
recommended:
1. Switch off the power supply and measure the resistance between the two CAN bus lines
Cx+ and Cx- with a multimeter. If the CAN bus cable is connected correctly, then the
resistance is approximately 60Ω.
For this the CAN bus line is terminated by a 120Ω resistor on each end (resulting
resistance is 60 Ω). This resistor is located on each PCB and may be activated by a
jumper (see description of each module in the annex of this manual).
The termination resistor of the FVE module version 1.01 is always activated. So in
some lift installations the CAN bus resistance may be 40Ω. However, the CAN bus
will work without problems in this case.
2. Check the shield connection of the bus cable (if shielded cable used): The screen should
be only connected on one side to 0(24V), preferably in the control cabinet. At the same
85/196