RPE User Guide

This user guide will describe how to use and operate the RP Engine controller (RPE) once an RPE have been created following the exercises of this lab.

Hardware requirements are located here: Hardware pre-requisites

You can use this user guide to:
► Understand the RPE measurements
► Understand the RPE SenseHAT LED output
► Operate the RPE using the SenseHAT joystick
► Use the RPE local dashboard

1. Understand the RPE measurements

The three devices (CPU, OSC, and ENV) in your RPE asset will submit its measured data on a regular basis to Maximo Monitor.

The last exercise in this lab ended with a screen shot of the data being delivered for the CPU device into the IoT Tool:

The properties are abbreviations of different measurements.

The Central Processing Unit (CPU) Device:

Metric	Unit	Description
cl	Percentage	CPU Load
ct	C	CPU Temperature
du	Percentage	Disk Usage of the SD card in the Pi
mu	Percentage	Memory Usage of the Pi

The Oscillator (OSC) device:

Metric	Unit	Description
ov	Volt	Oscillator Voltage
ot	Celcius	Oscillator Temperature
of	MHz	Oscillator Frequency

The Environment (ENV) device:

Metric	Unit	Description ç
eh	Percentage	Environment relativ Humidity measured by the SenseHat
ep	millibar	Environment atmospheric Pressure measured by the SenseHat
et	Celcius	Environment Temperature measured by the SenseHat

2. Understand the RPE SenseHAT LED output

Overview

You should look at the RPE SenseHAT from this angle, which means the power chord and/or the HDMI cable is pointing away from you:

The display consists of three areas:

• Connection status of the mqtt connections
• Day of week including operation status: Running / Idle
• Four bars representing selected measurements

Connection Status

This single LED at the left in the lower row is telling you the connection status to the Maximo Monitor instance.

All mqtt connections are connected

All devices are connected. It depends on knowing how many device connections it must look after as described in exercise 3.3.

All mqtt connections are trying to connect

All connections are either disconnected or connecting trying to establish a connection for all devices. This might be caused by lack of internet connectivity for the RPE.

At least one but not all connections are connected

This can be caused by faulty credentials in one or more mqtt out nodes, but not in all of them.

Waiting for connecting status

This may be caused by a mismatch between the number of connections defined and the number of mqtt out nodes the status node are listening to - as described in exercise 3.3.

Day of week including operation status

The seven LED's to the right in the lower row each represents a day in the week, starting with Monday.
Green means the RPE is running. The RPE will initiate a 5 minutes run under load every 0, 15, 30, 45 minutes past the top of the hour in the period: 8 am to 6 pm CET Monday to Friday. It will measure and submit data every 10 seconds while being in the running mode.
Red means the RPE is idle, meaning outside of working hours or in the weekend. It will not run any loads and will only measure and send every 20 minutes.

RPE is in working hour on a Tuesday

It is Tuesday between 8am and 6pm CET and all connections are up and running.

RPE is in idle mode on a Saturday

It is Saturday at any time as it is weekend ;-)

The four bars

The four bars represent the following four measurements:

1. cl: CPU Load
2. ct: CPU Temperature
3. ot: Oscillator Temperature
4. et: Environment Temperature (from the SenseHat)

Color	Meaning value in % or C is within
RED	X > 80
YELLOW	60 >= X <80
GREEN	40 >= X <60
GREEN	20 >= X <40
GREEN	X <20

Example 1

It is Wednesday between 8am and 6pm CET and all connections are up and running. The CPU Load is low, hence the temperatures are also relatively low.

Example 2

It is Wednesday between 8am and 6pm CET and all connections are up and running.
The CPU Load is high between 60 and 80%.
The CPU Temperature is between 60 and 80 C.
The Oscillator Temperature is above 80 C.
The Env, Temperature is between 20 and 40 C.

3. Operate the RPE using the SenseHAT joystick

Overview

This section will explain the options the SenseHAT joystick delivers to operate the RPE. You should look at it from this angle, which means the power chord and/or the HDMI cable is pointing away from you:

The joystick currently has 4 actions available:

• Down click
• Up click
• Enter click
• Hold to the left

Down Click

The down click shows scrolling text about network information changing between:

• IP Address in blue
• WiFi SSID in yellow
• MAC Address in green

Up Click

The up click shows scrolling text about RPE information changing between:

• The RPE ID in blue
• Software version of the Node-Red script in yellow
• Hardware version of the Raspberry Pi in green

Enter Click

Clicking on the enter button toggles the LED display off and on.

Hold Left

Holding the joystick left during some seconds will initiate an immediate SHUTDOWN of the RPE. This is in fact the best way to close down a Raspberry Pi minimizing the risk of damaging the SD card.

Handle with care!!

4. Use the RPE local dashboard

Overview

The RPE have a local dashboard where you can see the measurements and some additional information. They are accessible on http://<the RPE IP Address>:1880/ui.
The following three dashboards are available:

1. RP Engine – Shows some Rasperry Pi measurements (CPU and OSC values)
2. RP Environment – Shows some SenseHAT measurements
3. RPE Control – shows some RPE information

RP Engine – Idle Example

All measurements are within normal Idle mode.

RP Engine – Load Example

All measurements are either high or very high when running under Load mode.

RP Environment

These measurements are done in the SenseHat and covers:

1. Temperature (et)
2. Relative Humidity (eh)
3. Atmospheric Pressure (ep)

RPE Control

Information about the RPE software version and the Raspberry Pi hardware is available.
Two buttons are available to either Reboot or shutdown the RPE.

Handle with care!!