Power Management¶

Warning

To protect the device from damage, correct wiring and configuration of the power management settings is recommended.
The main purpose of the power management settings are to ensure that the device has a safe shutdown before the supply voltage (terminal 30/31) is disconnected.

The following subsections provide an overview of the individual power management functions.

There are three different conditions required for a CANlink® wireless 4000 to turn itself off.

Sleep-on-no-CAN time is elapsed
Time-to-sleep is elapsed
Shutdown Delay Time is enabled and has elapsed after Terminal 15 goes low

The following objects are used to configure the Power Management functionality:

Index	SubIndex	Object
`0x3333`	`0x08`	Time in seconds to sleep mode
`0x3333`	`0x29`	Sleep timer active flag
`0x3333`	`0x32`	PMM Shutdown Delay Time
`0x3333`	`0x37`	Power Management Shutdown Enable
`0x3333`	`0x41`	PMM Sleep on no CAN time

Sleep-on-no-CAN¶

The Sleep-on-no-CAN setting is used when the device should automatically enter sleep mode when there is no CAN messages received by the device on either CAN bus within a specified time period.

Object 0x3333:0x41 [PMM Sleep on no CAN time] is used to set the CAN message timeout sleep period.
The timer is restarted with every CAN message received.

Set 0x3333:0x41 to the desired timeout in milliseconds.
The device will go to sleep when
1. no CAN message has been received in this time, and
2. CLAMP15 is low
The device will automatically wake upon
1. Any CAN traffic, or
2. A high signal on CLAMP15.

Note

This value should be less than the timeout for 0x3333:0x80 [Wireless Interface Watchdog Period] (if enabled) to prevent the reset from the Wireless Watchdog resetting this counter.
See Wireless Watchdog.

Time-to-sleep¶

Object 0x3333:0x08 [Time in seconds to sleep mode] is used to set the sleep timeout period.
This is volatile (reset every boot), and must be set by an external controller every time the device should sleep.

Essentially, this value tells the device “Go to sleep (x) seconds after receiving the last CAN message when the ignition is off”.

This timer is restarted with every CAN message, and every change to CLAMP15.

Set 0x3333:0x08 to the desired timeout in seconds.
The device will go to sleep
1. After this period has elapsed with no CAN messages on either bus, and
2. CLAMP15 is low, and
3. 0x3333:0x29 [Sleep timer active flag] is set to 0x01
The device will automatically wake upon
1. Any CAN traffic, or
2. A high signal on CLAMP15

Tip

The 0x3333:0x08 [Time in seconds to sleep mode] function will be disabled upon boot, and must be enabled again to occur.

Shutdown Delay Time (Terminal 15 Monitoring)¶

Object 0x3333:0x32 [PMM Shutdown Delay Time] is used to set the ignition timeout period. The device waits for a period of time after the ignition has been turned off (CLAMP15 turns low).

This timer is restarted with every CAN message, and every change to CLAMP15.

TO ENABLE

Set 0x3333:0x32 [PMM Shutdown Delay Time] to the desired timeout in seconds.
Set 0x3333:0x37 [Power Management Shutdown Enable] to 0x80.

The device will go to sleep this many seconds after:

ignition is off (CLAMP15 is low), and
no CAN message has been received
0x3333:0x37 [Power Management Shutdown Enable] is set to 0x80

The device will automatically wake upon:

Any CAN traffic on either CAN bus, or
A high signal on CLAMP15

TO DISABLE

Set 0x3333:0x37 [Power Management Shutdown Enable] to 0x00.

Note

The recommended minimum period for 0x3333:0x32 [PMM Shutdown Delay Time] is 5s.

Power Management Summary¶

In cases, to enter sleep:

0x3333:0x32 [PMM Shutdown delay time] has a non-zero value, and
0x3333:0x37 [Power Management Shutdown Enable] is set to 0x80, and
CLAMP15 must be low, and
no CAN message has been received in the 0x3333:0x32 [PMM Shutdown delay time] period.

The device will automatically wake upon:

Any CAN traffic on either CAN bus, or
A high signal on CLAMP15

These three Sleep configurations operate simultaneously.