Setting the Node Number and Baud Rate

3.3.1 Setting the Node Number

CANopen supports 127 nodes on a bus, with an address range of 1 to 127 (01h...7Fh). The address (node ID) of a node is set using rotary switches 1 and 2 of the bus coupler. The rotary switches are hexadecimally coded. Rotary switch 1 is used to set the second digit (LSB) or the CAN node address, while rotary switch 2 is used to set the first digit (MSB).

Rotary switch 2 may be set to a maximum value of 7 (node ID: max. 7Fh).

The settings on the rotary switches are read once during power-up. The node ID cannot be changed during operation; therefore, you should only change the node ID when the power is off.

3.3.2 Setting the Baud Rate

The rotary switch setting 00h is of particular significance. According to CANopen speci-fications, this "ID" is not a permissible node address and can be used for configuration purposes. On the transCON bus coupler, you can use it to activate the mode for setting and reading the baud rate.

To set the baud rate, you need the transCON PS-24VDC power supply module. The type and quantity of any other modules connected is immaterial. Connected I/O modules are ignored, and flashing error LEDs on the modules do not have any effect on the setting process.

The following describes how to set the baud rate of the bus coupler.

The factory setting for the baud rate is 125 kBaud. The table below shows the baud rates that apply to the settings for rotary switch 1:

Setting on rotary switch 1 Transmission rate (kBaud)

01 10

02 20

03 50

04 100

05 125 (factory setting)

06 250

07 500

08 1000

If you should wish to read the set baud rate, refer to section 3.3.3, "Reading the Baud Rate" on page 3.3.

To set the baud rate, proceed as follows:

De-energise the bus coupler (e.g. by disconnecting the power supply).

1.

Set both rotary switches on the bus coupler to "0".

2.

Reconnect the bus coupler to the voltage supply. The

3. TX LED will flash and the ERR

and PWR LEDs will light up continuously during the entire setting process.The TX LED will flash for five seconds if the switch setting is not changed. Each time the switch setting is changed, this five-second interval will start again. If the five-second interval expires, the TX LED will light up continuously and there will be no need to make any further changes in this setting cycle. To exit setting mode, go to step 6.

Set rotary switch 1 to the required value from the table above (between "1" and "8").

4.

If the new baud rate is the same as the old one, the RX LED will light up. Switch 2 remains at "0". Now wait for five seconds. To exit setting mode, go to step 6.

Once the five-second interval has expired, the TX and RX LEDs will light up continu-5.

ously. The new baud rate will be accepted.

It will not be possible to make any further changes in the present setting cycle.

6.

To exit setting mode, remove the power supply from the bus coupler again. Set the 7.

rotary switch to a node ID ≠00h

Restore the voltage supply. Only the PWR LED will light up, indicating that the bus 8.

coupler is ready for operation.

NOTICE

Avoid any interruption in the voltage supply during the setting procedure. This may lead to all the values stored in the bus coupler and the configuration being lost.

CANopen operation can be continued as soon as the node ID has been set to something other than "00h" after power has been restored. Restoring the power following "00h"

mode has no effect insofar as the rotary switch setting is not accepted as the node ID (i.e.

the previously set node ID is retained). You should, however, ensure that the correct node ID is accepted after an unintentional power failure.

3.3.3 Reading the Baud Rate

To read the baud rate, follow the same steps as those outlined in "Setting the Baud Rate":

De-energise the bus coupler.

1.

Set both rotary switches on the bus coupler to "0".

2.

Reconnect the bus coupler to the voltage supply. The TX LED will flash and the ERR 3.

and PWR LEDs will light up continuously during the entire reading process.

The TX LED will flash for five seconds. When the TX LED is flashing, the bus coupler is 4.

in programming mode. Wait for five seconds before making any changes to the switch setting, in order to ensure that the bus coupler exits programming mode.

The TX LED will now light up continuously, and the bus coupler will be in reading 5.

mode. In this mode, the RX LED lights up at the moment when the rotary switch setting matches the programmed baud rate.

You can change the setting for rotary switch 1 until the RX LED lights up. You can read 6.

the programmed baud rate from the table in the section "Setting the Baud Rate".

To exit reading mode, remove the power supply from the bus coupler again.

7.

If you now wish to change the baud rate, proceed as described in "Setting the Baud 8.

Rate". Otherwise, set a valid node ID; the bus coupler will then be ready for operation.

NOTICE

Under no circumstances may the rotary switch be changed while the TX LED is flashing. You use it to program the baud rate as described in the chapter "Setting the Baud Rate".

To make wiring easier, the bus coupler input has duplicate connections. The corresponding signals are connected on the board. The connections on the upper part of the module have no function (NC = not connected).

You can find further information on connecting and configuring the CAN bus in sec-tions 3.4 to 3.7.