Defining the redundancy level

Please note the distinction between the CS141 and the UPS - Normally, the UPS cannot send a message, only the CS141 connected to the UPS. This can be an external device via RS232 / RS485 or also an internal slot card. Technically they are independent devices, but if you follow the path of the signal starting from the UPS, it is easier to visualize if you consider the CS141 as a component and therefore the UPS as the "transmitter"...

If there is more than one UPS in a network, systems can be connected redundantly. In this case, the failure of one of two power supplies may not necessarily trigger an emergency shutdown.

RCCMD can be set to take this network configuration into account. The configuration will be carried out as follows:

1. Under connections, define static valid IP addresses of all valid RCCMD senders (including the UPS)
2. At redundancy, decide, which of the IP addresses will be included into the Redundancy,
3. Set up the redundancy level:

The redundancy level follows a clear scheme: As soon as one of the selected valid transmitters sends a shutdown, the redundancy level is used to determine how many other transmitters must also send a shutdown:

0. – No other signal is required, RCCMD will trigger shutdown process immediately.
1. – At least one more of the selected transmitters must confirm a shutdown.
2. – At least two more of the selected transmitters must confirm a shutdown.

– At least three more of the selected transmitters must confirm a shutdown.

The maximum redundancy is automatically adjusted to the number of IP addresses of valid transmitters selected under "Group". You can therefore never select more units than are actually available. Please keep in mind, if you select 3 devices for redundancy, you may also configure that 2 of 3 can advise a shutdown. But in this case, you will not be able to define which of them will send.

Redundancy shut down override

It can always happen that a shutdown has to be carried out even though both UPS systems are in order and the main power supply is running faultlessly - a typical scenario here would be a defective air conditioning system, which would result in the overheating of servers and other infrastructure - and only one of your CS141 monitors them additionally.

In this case, the harmed server should also shut down in time before getting damaged by overheating. RCCMD offers several options to solve such a problem:

1. Write a small shut down script and place it within the RCCMD installation folder. This script can be triggered directly via the RCCMD job “RCCMD Execute”.

With this command, RCCMD offers an option to start any script that triggers any command - including a scripted shutdown routine. Since this is not the job "RCCMD shutdown", which was specifically associated with the UPS, the RCCMD client would execute this command accordingly - with an entry in the connections table, the IP address of the sender is allowed to send commands.

How to use a third CS141 independently

As an example, the third CS141 was configured to handle environmental control only:

Depending on your personal style and the configuration level, up to 8 analogue sensors and 4 digital inputs can be possible and may include fire and smoke sensors, glass breakage sensors, access control systems, gas detectors, temperature sensors, level detectors, digital alarm wires, battery management systems, motion detectors, etc.

In this case, you would enter all three CS141s at Connections, but for redundancy, you would only select the two transmitters that deal directly with the UPS and the emergency shutdown in case of problems with the UPS. The third CS141, which is only responsible for the environmental control systems, could in this case send an RCCMD shutdown independently.

Withdrawal of a shutdown:

From a redundancy of 1 (= two units), a shutdown can also be reversed - this is the case, for example, when the main power supply of a UPS has been restored. This is done at the transmitter with the custom command "WAKEUP" - this is the signal for the RCCMD client that the cause of a fault has been eliminated, and the counter is corrected accordingly.

Note: 

In this context, each CS141 is generally only allowed to send one shutdown signal. The RCCMD client remembers which transmitter has already sent and which transmitter has sent a corresponding counter command and is therefore authorized again. Restarting the RCCMD client - usually a start after shutting down the computer - generally resets this counter to 0. So, if you test the incoming signals after configuration, be sure to restart the RCCMD client again to prevent accidental shutdown. 

Also keep in mind to enable the Heartbeats

Redundancy and heartbeats are directly dependent on each other: RCCMD needs to know which devices to check. The list of devices to be checked is taken from the list that you enter under Connections. Using the heartbeat settings, you tell RCCMD that in the event of a power failure (an incoming shutdown signal), an availability test must be carried out.