[ENG] 7.1. [DKSF 54.3 IU] What Is «Watchdog» and How to Configure It?

«Watchdog»  is a specific operation mode of a relay channel that polls specified addresses using ping (ICMP Echo) constantly, with a specified periodicity. If there is no response, a device connected to terminals of a corresponding relay is rebooted.

If indicated IP addresses are outside IP subnet of a device, there is a need to indicate a gateway address to the external network on the page «SETUP» of a device web interface.

To configure the module «Watchdog», there is a need to go to the page «WATCHDOG» of a device web interface:

Configuring a module Watchdog of a NetPing 4PWR-220 v4SMS device

where:

Enable Control of Relay – is the activation of a relay control. If a checkbox is not checked, a relay will not be controlled by a module «Watchdog».

Memo – is a description of a relay that is specified in the field «Memo» on the page «RELAYS» of a device web interface.

Polling of Address A, B, C – is a set of checkboxes that allow indicating addresses that are included in polling individually. On default: checkboxes are not checked.

If none checkbox is checked, or if IP addresses for checked checkboxes are not specified, polling will not be executed and the mode «Watchdog» will be de-facto disabled.

Address A (B, C) – is a field or viewing or changing polling addresses. It is acceptable to indicate an IP address the same as a domain name. It is possible to configure up to three addresses. An empty field disables polling. On default: address is not specified.

Reset counter (cleared on firmware reboot) – is an information field that shows how many times a channel had been rebooted as a result of the actions of the module «Watchdog». A counter does not include the number of reboots in a «manual mode». A counter is reset when a power supply of a NetPing device is switched off.

Ping polling period, 10-300s – is a field for setting a time interval after which repeated pings are sent to indicated IP addresses after receiving a response from them. On default: 15 s.

Ping Timeout, 600-9000ms – is a field for setting a timeout before repeating ping. A value must exceed a typical ping response time for the network with some space exclude faulty triggering of the module «Watchdog». On default: 1000 ms.

Max Ping Repeats after Timeout – is a field for setting a maximum number of attempts to get a response to «ping». If a number of retries is over, an IP address is considered «silent». It is desirable so that a period of ping repeat exceeds a ping timeout multiplied by a maximum number of retries. If this condition is not fulfilled, then a new polling cycle will be postponed until an indicated number of retries is over. On default: 8.

Reset Duration, 1-900s – is a field for setting time for which a device connected to a power supply socket is de-energized to initiate reset and reboot. On default: 12 s.

Ping Polling Pause After Reset, 1-3600s – is a field for setting time for which polling is stopped after switching on a socket of a power supply channel. A pause is necessary so that a device initiated and restored the functioning of its network interfaces. Otherwise, it is possible that the module «Watchdog» will be endlessly triggered. On default: 15 s.

Limit Number of Reset Retries, 1-255, 0 - Off – is a field for setting a number of consequent unsuccessful resets after which the functioning of «load» is not restored and there is still no response to ping. It can happen when there is a stable failure of the «load» that is not possible to restore by power switching on-off. When the limit of repeats is reached, the resets are stopped, but periodic polling is continued. Resets are unlocked when a response to ping is received. Stopping resets and restoring of a usual operation order after responding to ping are registered in a log. A parameter value 0 disables the limit. On default: 0

Reset Polarity – is a field that allows indicating what action will be executed to reboot connected load: «Switch Relay Off» or «Switch Relay On» on an output power supply socket. On default: Switch Relay Off.

Reset Condition Logic – determines a condition at which a device connected to an output power supply socket will be reset.

No reply from any of Address A,B,C – a connected device will be rebooted if at least one of these addresses does not respond.

No reply from all of Address A,B,C – a connected device will be rebooted only if all indicated addresses for polling do not respond.

No reply from Address А and from one of B,C – a connected device will be rebooted if address A did not respond and one of addresses В or С, or both B and C didn't respond either.

No reply from Address А, but B or C replies – a connected device will be rebooted only if address A didn't respond but address B and/or address C did respond. I.e. if all addresses do not respond, a connected device will not be rebooted.

After setting all necessary parameters, click the button «Apply changes», so that a device executes a command.

If one of the parameters is set incorrectly, it will be highlighted in red:

Incorrect setting parameters in a module Watchdog of a NetPing device

It is necessary to correct a value of a parameter and click the button «Apply changes» again.