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EPOS4 Gateway / CAN
Configuration
Version: 2018-02-22
Author: ROMA
Document: EPOS4-Gateway_CAN-Network-Configuration.docx Page: 2 / 6
Bus termination
Do not miss to add bus termination resistors (120 Ohm) or configure the bus termination by the
corresponding DIP switch at both physical end points of the CAN network.
Quite often the CANopen devices with the lowest (= 1) and highest Node IDs are the ones
located at the physical end points of the bus but this is not mandatory. Therefore it is
recommended to check by the CAN wiring which CANopen devices are actually placed at
the physical end points of the CAN bus and require the bus termination.
The EPOS4 in use as the gateway is typically one physical end point of the CAN bus, i.e.
add or configure the bus termination for this EPOS4 in that common case.
Add or configure the bus termination for the CANopen device (e.g. EPOS2 or EPOS4) at the
other physical end point of the CAN network.
Ensure that there is no additional bus termination configured or resistors present somewhere
in between the CAN network. The measured resistance in between the “CAN High” and
“CAN Low” has to be about 60 Ohm in power-off state.
CAN bit rate configuration
It is important that at least one device in the CAN network has a “Fixed CAN bit rate”
configuration.
The default “CAN bit rate” configuration of the EPOS4 DIP switch is “Automatic bit rate”.
IMPORTANT:
Ensure that at least one EPOS4 (typ. gateway) has set the DIP switch “Auto bit
rate”to “OFF” and a “Fixed CAN bit rate” is configured by object 0x2001.
Remark:
If the DIP switch “CAN automatic Bit Rate Detection” is not set to “OFF”, the bit rate
configured by the object 0x2001 is not taken into account.
In case of a “CAN bit rate” configuration higher than 125 kbit/s it is mandatory that the
bus terminations, bus topology as well as the CAN wiring is perfect and not
influenced by EMI. Otherwise CAN communication might fail later on.
Do not miss to save an updated “Fixed CAN bit rate” by “Saving All Parameters”
before you power down / power up all devices again.
It is sufficient to configure just one CANopen device for a “Fixed CAN bit rate”. Other EPOS2
or EPOS4 can keep the “CAN Automatic Bit Rate detection” set.
If more than one CANopen device has a “Fixed CAN bit rate”, please ensure that the
“CAN bit rate” is the same for any device with a “Fixed CAN bit rate”configuration.
General note:
Please refer to the “Hardware Reference” of the EPOS2 or EPOS4 in use concerning the DIP switch location
and configuration in case of “Housed” or “Compact”product types or the pin assignment of “Modules”.
