Layer Setting Services (LSS)

The LSS protocol is used to change the node id and baud rate of the target CANOpen device (slave). To change these values, configuration state should be set first by master. Then modify the node id and the baud rate. There are two options to switch from waiting state to configuration state. One is to switch all the slave at once, the other way is to switch only one slave. The former can be used to set baud rate for all the slaves. The latter can be used to change node id one by one.

Once you finished the setting, the values should be saved to non-volatile memory. Finally, you can switch to LSS waiting state.

Note

Some method and constance names are changed:

send_switch_mode_global() ==> send_switch_state_global()
network.lss.CONFIGURATION_MODE ==> network.lss.CONFIGURATION_STATE
network.lss.NORMAL_MODE ==> network.lss.WAITING_STATE

You can still use the old name, but please use the new names.

Note

Fastscan is supported from v0.8.0. LSS identify slave service is not implemented.

Examples

Switch all the slave into CONFIGURATION state. There is no response for the message.

network.lss.send_switch_state_global(network.lss.CONFIGURATION_STATE)

Or, you can call this method with 4 IDs if you want to switch only one slave:

vendorId = 0x00000022
productCode = 0x12345678
revisionNumber = 0x0000555
serialNumber = 0x00abcdef
ret_bool = network.lss.send_switch_state_selective(vendorId, productCode,
                                    revisionNumber, serialNumber)

Or, you can run fastscan procedure

ret_bool, lss_id_list = network.lss.fast_scan()

Once one of sensors goes to CONFIGURATION state, you can read the current node id of the LSS slave:

node_id = network.lss.inquire_node_id()

Change the node id and baud rate:

network.lss.configure_node_id(node_id+1)
network.lss.configure_bit_timing(2)

This is the table for converting the argument index of bit timing into baud rate.

idx

Baud rate

0

1 MBit/sec

1

800 kBit/sec

2

500 kBit/sec

3

250 kBit/sec

4

125 kBit/sec

5

100 kBit/sec

6

50 kBit/sec

7

20 kBit/sec

8

10 kBit/sec

Save the configuration:

network.lss.store_configuration()

Finally, you can switch the state of the slave(s) from CONFIGURATION state to WAITING state:

network.lss.send_switch_state_global(network.lss.WAITING_STATE)

API

class canopen.lss.LssMaster[source]

The Master of Layer Setting Services

RESPONSE_TIMEOUT = 0.5

Max time in seconds to wait for response from server

activate_bit_timing(switch_delay_ms)[source]

Activate the bit timing.

Parameters:

switch_delay_ms (uint16_t) – The slave that receives this message waits for switch delay, then activate the bit timing. But it shouldn’t send any message until another switch delay is elapsed.

configure_bit_timing(new_bit_timing)[source]

Set the bit timing.

Parameters:

new_bit_timing (int) – bit timing index. 0: 1 MBit/sec, 1: 800 kBit/sec, 2: 500 kBit/sec, 3: 250 kBit/sec, 4: 125 kBit/sec 5: 100 kBit/sec, 6: 50 kBit/sec, 7: 20 kBit/sec, 8: 10 kBit/sec

configure_node_id(new_node_id)[source]

Set the node id

Parameters:

new_node_id (int) – new node id to set

fast_scan()[source]

This command sends a series of fastscan message to find unconfigured slave with lowest number of LSS idenities

Returns:

True if a slave is found. False if there is no candidate. list is the LSS identities [vendor_id, product_code, revision_number, serial_number]

Return type:

bool, list

inquire_lss_address(req_cs)[source]
Read the part of LSS address.

VENDOR_ID, PRODUCT_CODE, REVISION_NUMBER, or SERIAL_NUMBER

Parameters:

req_cs (int) – command specifier for request

Returns:

part of LSS address

Return type:

int

inquire_node_id()[source]

Read the node id. CANopen node id must be within the range from 1 to 127.

Returns:

node id. 0 means it is not read by LSS protocol

Return type:

int

send_identify_remote_slave(vendorId, productCode, revisionNumberLow, revisionNumberHigh, serialNumberLow, serialNumberHigh)[source]

This command sends the range of LSS address to find the slave nodes in the specified range

Parameters:

  • vendorId (int)

  • productCode (int)

  • revisionNumberLow (int)

  • revisionNumberHigh (int)

  • serialNumberLow (int)

  • serialNumberHigh (int)

Returns:

True if any slave responds. False if there is no response.

Return type:

bool

send_switch_mode_global(mode)[source]

obsolete

send_switch_state_global(mode)[source]

switch mode to CONFIGURATION_STATE or WAITING_STATE in the all slaves on CAN bus. There is no reply for this request

Parameters:

mode (int) – CONFIGURATION_STATE or WAITING_STATE

send_switch_state_selective(vendorId, productCode, revisionNumber, serialNumber)[source]

switch mode from WAITING_STATE to CONFIGURATION_STATE only if 128bits LSS address matches with the arguments. It sends 4 messages for each argument. Then wait the response from the slave. There will be no response if there is no matching slave

Parameters:

  • vendorId (int) – object index 0x1018 subindex 1

  • productCode (int) – object index 0x1018 subindex 2

  • revisionNumber (int) – object index 0x1018 subindex 3

  • serialNumber (int) – object index 0x1018 subindex 4

Returns:

True if any slave responds. False if there is no response.

Return type:

bool

store_configuration()[source]

Store node id and baud rate.

class canopen.lss.LssError[source]

Bases: Exception

Some LSS operation failed.