IoT Predictive Maintenance Sensor Manual

Overview

Features

  • Industrial Grade IoT Wireless Predictive Maintenance Sensor
  • AC Current Range 0-100A RMS Measurement
  • 3-axis Vibration Sensor with RMS, MAX and MIN
  • Calculates g Vibration Data Across ±16g Range with Low Pass Filter
  • Frequency Range (Bandwidth) up to 408 Hz Samples up to 952Hz
  • High Grade K type thermocouple Connector and Probe
  • Ideal Sensor For Machine Health Monitoring
  • Builtin Offset and Gravity vector removal filters
  • Operating Temperature Range -40 to +85 °C
  • 1-Mile Range with 2.4GHz or 2 Mile Range with 900MHz On-Board Antenna
  • Superior LOS Range of up to 28 miles with 900MHz High-Gain Antennas
  • Interface to Raspberry Pi, Microsoft Azure, Arduino and More
  • Example Software for Visual Studio and LabVIEW
  • Wireless Mesh Networking using DigiMesh®
  • Up to 256 Sensor Nodes per Network
  • Open Communication Protocol for custom interfacing applications
  • Multiple Modes of Operation (Configuration and Run mode)
  • Wireless Sensor and Radio Configuration feature
  • Default Factory settings Restore option
  • Power Efficient Built-in Sleep mode
  • User Configurable Sleep duration
  • Up to 500,000 Transmissions from 2 AA Batteries
  • Reliable Transmission incorporating packet Retries
  • Secure Transmission using AES-128 Encryption
  • Real time battery status

Applications

  • Industrial Current Monitoring
  • Pump, Motor,Generators Electrical Behavior Analysis
  • Future  Fail Detection In Machines
  • Ideal Component for Predicative Maintenance
  • Handheld Current monitoring equipment
  • Key component of predictive maintenance
  • Predictive Maintenance Data To Cloud Like AWS/Azure

Description

Introducing NCD’s Long Range Industrial IoT Wireless Predictive Maintenance Sensor, boasting up to a 2 Mile range using a wireless mesh networking architecture.  This IoT Wireless Predictive Maintenance Sensor consist a Vibration Sensors, Thermocouple , AC Split Core Current Sensor and Ambient Temperature Sensor. This IoT Wireless Predictive Maintenance Sensor Samples the vibration, RMS current and temperature data and sends after a fixed user designed interval over the wireless network. The sensor comes with three 1.25 meter long split core current sensors, 1 Meter Long Vibration Probe and 1 Meter Long thermocouple probe which makes installation easy.

3-Axis Vibration Sensor Characteristics —  During Power-Up, this vibration sensor learns “normal” base-line vibration from the monitored device.  This base-line vibration is subtracted from regular sampled vibration readings to improve relevant vibration data.  Ideally, the monitored device should be off while the sensor is learning.  Once the sensor stabilizes and starts sending data, the device/machinery being monitored can be powered on.  This Industrial IoT wireless vibration sensor samples 3-axis of Vibration data for 500ms and then calculates RMS, Maximum, and Minimum vibration readings. This sensor combines these data with temperature data in a data packet, and transmits the result to modems and gateways within wireless range.  Once transmission is complete, the vibration sensor goes back to sleep, thus minimizing power consumption.

Thermocouple  Sensor Characteristics — Long Range Industrial IoT Wireless Predictive Maintenance Sensor is capable of measuring extreme high and low temperatures.  This wireless thermocouple includes one 5SRTC-TT-K-24-36 K-Type thermocouple probe from Omega.com with a 1m, 24 AWG connection cable, rated for temperature measurement applications up to 260°C (500°F) with an accuracy of ±2.2°C. This wireless thermocouple device comes with K-Type connector, which can be used to connect higher temperature range thermocouple if needed. This sensor has in built hot and cold junction to provide highly accurate reading.  This wireless IoT thermocouple product is an ideal product for high temperature measurements, industrial boiler temperature measurements, liquid temperature measurement, and temperature monitoring of food storage units.  This Long Range Industrial IoT Wireless Predictive Maintenance Sensor product is designed to consume extremely low power and send data at extremely long distances of up to 2 miles line-of-light or up to 28 miles using high gain antennas.

Powered by just 4 AA batteries and an operational lifetime of 500,000 wireless transmissions, a 10 years battery life can be expected depending on environmental conditions and the data transmission interval.

To complete a network with an industrial sensor at one end, a Zigmo/Router is required at the receiving end (PC end) that receives data from sensor. A set of sensor and Zigmo is shown in following figure.

Wireless Vibration Sensor
Sensor with Zigmo/Router

Getting Started

The Wireless Predictive Maintenance Sensor and Zigmo/Router come pre-programmed and work out of the box. In this section we will setup a sensor and Zigmo link and start receiving data on our PC. Though this guide shows how to visualize data on LabVIEW utility, you can also use a simple serial terminal to see raw data by following these steps.

Resources Required

Note: The Wireless Sensor comes with external power enabled, for battery conservation during shipping. To enable battery power, open the enclosure and set the PS (power select) jumper which is parallel to the marking line on the board.

Steps

  1.  Power-up the Wireless Sensor and make sure its antenna is installed
  2. Connect your Zigmo/Router to your PC. You can also use any other ncd modems and gateways.
Figure 1: Connect Zigmo/Router to PC
  1. Identify the serial port allocated to it by going into device manager (You can also find the serial port using Digi provided utility XCTU)
At this stage, both the Sensor and Zigmo have automatically established communication and the data can be read from the serial port at which Zigmo has been installed.
Figure 2: Serial port identification
  1. Install the LabVIEW utility for the sensor you are working with. Run this utility.
  2. Press the port configure button and select the PORT you identified in step 3. Select baud rate of 115200 and press OK.
Figure 3: LabVIEW Utility for Sensor

Troubleshooting

Changed/Unknown setting at sensor end

One of the issues for unsuccessful communication can be a changed setting at the sensor end due to which the sensor and Zigmo are unable to establish a connection. You can resolve this problem by going back to the factory default settings which are provided in Table 1. Please refer to Figure 7 and follow steps shown in it for applying factory default settings.

Once the sensor resets it will start sending a frame every 600 seconds after factory reset.

Please refer to the detailed document available to Digi website to understand X-bee communication parameters and its operation mechanism.

Table 1: Default Parameters programmed after Factory reset sequence

Changed/Unknown setting at PC end

Sometimes a changed setting at Zigmo end, whether intentional or unintentional, can cause a network failure and no data reception at PC end. To fix this issue when the sensor end is operating at factory default settings you will have to bring the Zigmo/Router to factory default settings as well. For that, please download the configuration file for Zigmo from our website. You will also require XCTU utility provided by Digi.

After installing XCTU Utility, run it and go to add a radio module. Select the serial port at which Zigmo is connected and press finish. This will connect the Zigmo to XCTU.

Figure 5: Connecting Zigmo/Router to XCTU

After double clicking the added module, a list of parameters will be displayed on the right side. Select the load configuration file from the top and select configuration file form the location where you downloaded it earlier.

Now press the write button on top to write these parameters. Close the XCTU utility and open the LabVIEW utility and follow the steps in getting started section to communicate with sensor.

Figure 6: Loading a default profile to Zigmo/Router

Modes of Operation

This module incorporates 2 modes of operation, these are

  • Run Mode
  • Configuration Mode


Run mode is the standard mode, the module will always enter Run mode if no button is pressed during Power-up/Reset. Configuration mode is intended to configure sensor parameters and the X-bee parameters on the sensor end. Note that the Sensor end X-bee is only configurable via the sensor controller using the commands provided in device manual. Figure 7 illustrates these modes.

The device sends a startup packet which can be used to determine the mode in which it is operating. These packets are shown in Table 2.

Mode Selection Process

The CFG button on the module is used to change mode. If CFG button is pressed and the module reset button is pressed, the module will enter the configuration mode. The amount of time CFG button has to be pressed is shown in Figure 7.

Note that settings only take effect after the reset.

Figure 7: Mode Selection Process
Frame Communication at Power up

In figure 8,  Mode bytes highlighted in red can be compared with the values provided in Table 2 to determine the mode in which the sensor is operating. Node ID is the ID of the given sensor while sensor type determines the type of sensor. Both of these can be used to determine the exact sensor which is sending the information.

A shown in second column in Table 2, the sensor configures its PAN ID automatically depending upon the mode it is working in. During factory reset it sets the PAN ID to the value given in table therefore the factory reset frame will only be received if your Zigmo/Router PAN ID matches this ID. Please note that right after factory reset the sensor enters configuration mode therefore its PAN ID is changed again and a new frame is generated. All 3 type of frames are shown in Figure 9, Figure 10 and Figure 11.

 

The factory default settings are shown in Table 1. For parameter description please refer to the section on configuration.

Table 2: Mode Bytes for different sensor modes (* this frame is followed by configuration frame as shown Figure 7)
Figure 8: Typical Communication at Power Up, Transmitted packet (left) Received packet (right)
Figure 9: Run Mode Power up frame
Figure 10: Configuration Mode Power up frame
Figure 11: Factory Default Power up frame

Run Mode

Run mode is the default mode of operation of this sensor. In this mode the sensor sends periodic packets to destination receiver. During the time it is not sending packets, it sleeps and conserves power. Sensor end X-bee operates in API mode and sends packets to the saved destination address on the network specified by the saved PAN ID. Figure 12 illustrates an API packet transmission and reception.

Packet reception at receiver end is ensured by the device by retrying up to 3 times if no acknowledgement is received that the packet has been successfully received. The device uses the acknowledgement functionality available in API mode in X-bee devices therefore user does not need to worry about sending acknowledgements for every packet.

Figure 12: Transmit packet detail (left), Received packet detail (right)

The detail for API packet received at PC end can be read from the X-bee manual available from Digi. The detail of Payload section of packet is shown in Table 3.

Typical response from the device in Run mode is shown in Figure 13 and Figure 14. The utility shown in Figure 14 can be downloaded from the website.

Frame FieldOffset (Payload Section)Fixed Value
(if any)
Description
Header00x7F
Header to differentiate various type of packets
Node ID10x00 Factory Default
Node ID to differentiate up to 256 nodes in a network. User configural values
Firmware2
Used to determine firmware version programmed in the device
Battery VoltageMSB 3

Sampled battery voltage of the device.

Battery Voltage=((Battery Voltage MSB x 256+Battery Voltage LSB) x 0.00322 V

LSB 4
Packet Counter5
It is an 8-bit counter that increments with each packet transmission. It can be used to detect missing packets.
Sensor TypeMSB 60x00
Two bytes to determine sensor type. It can be used in conjunction with Node ID to create sensor networks of up to 256 nodes for a single type of sensor and multiple such networks can coexist and can be differentiated in processing software on PC end
LSB 70x32
Reserved80x00

For future use

Vibration RMS 9/X[0]

Vibration RMS X-axis Data (24 bit Signed Output)

        Vibration (mg) = ((X[0]<<16)+(X[1]<<8)+X[2])/100

(Saving directly to 32 bit integer will give wrong result

 10/X[1]
 11/X[2]
 12/Y[0]

Vibration RMS Y-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Y[0]<<16)+(Y[1]<<8)+Y[2])/100

(Saving directly to 32 bit integer will give wrong result

 13/Y[1]
 14/Y[2]
 15/Z[0]

Vibration RMS Z-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Z[0]<<16)+(Z[1]<<8)+Z[2])/100

(Saving directly to 32 bit integer will give wrong result

 16/Z[1]
 17/Z[2]
Vibration Max 18/X[0]

Vibration Max X-axis Data (24 bit Signed Output)

        Vibration (mg) = ((X[0]<<16)+(X[1]<<8)+X[2])/100

(Saving directly to 32 bit integer will give wrong result

 19/X[1]
 20/X[2]
 21/Y[0]

Vibration Max Y-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Y[0]<<16)+(Y[1]<<8)+Y[2])/100

(Saving directly to 32 bit integer will give wrong result

 22/Y[1]
 23/Y[2]
 24/Z[0]

Vibration Max Z-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Z[0]<<16)+(Z[1]<<8)+Z[2])/100

(Saving directly to 32 bit integer will give wrong result

 25/Z[1]
 26/Z[2]
Vibration Min 27/X[0]

Vibration Min X-axis Data (24 bit Signed Output)

        Vibration (mg) = ((X[0]<<16)+(X[1]<<8)+X[2])/100

(Saving directly to 32 bit integer will give wrong result

 28/X[1]
 29/X[2]
 30/Y[0]

Vibration Min Y-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Y[0]<<16)+(Y[1]<<8)+Y[2])/100

(Saving directly to 32 bit integer will give wrong result

 31/Y[1]
 32/Y[2]
 33/Z[0]

Vibration Min Z-axis Data (24 bit Signed Output)

        Vibration (mg) = ((Z[0]<<16)+(Z[1]<<8)+Z[2])/100

(Saving directly to 32 bit integer will give wrong result

 34/Z[1]
 35/Z[2]

 Ambient Temperature data (16 bit Signed Output)

Temperature Data 36/T[0]

  Temperature (°C) = (T[0]<<8)+T[1]

 

Temperature

Data 37/T[1]

 Temperature data (32 bit Signed Output)Temperature Data 38/T[0]

Temperature data

Temperature(signed)  

    (data[38]<<24)+(data[39]<<16)+(data[40]<<8)+(data[41])

=  ———————————————————————-

                                         100

Temperature Data 39/T[1]
Temperature Data 40/T[2]
Temperature Data 41/T[3]
Current data (24 bit Output)Current Data [42] 

Current (unsigned) – mA

Current (mA) = ((Datata[42]<<16)+(Datata[43]<8)+Data[44])/1000

Current Data [43] 
Current Data [44] 
Figure 13: Run mode packets being received in a terminal (Hex mode)

Configuration Mode

Configuration mode is intended to setup the device over the wireless link. Entering configuration mode was already explained in the section “mode selection procedure”. User can also setup X-bee communication and networking parameters using this mode via PC. Note that settings only take effect after reset and are stored inside the device.

In configuration mode, the device sets its X-bee pan id to 7BCD (Hex). Also, the destination address used by the sensor is extracted from the incoming packet (source address). This ensures that once you put a device in configuration mode you just need to change the PAN ID of your Zigmo to match with sensor and start configuring your device. You can change the PAN ID of your Zigmo using XCTU from Digi. If you use our LabVIEW utility, it will automatically change Zigmo PAN ID once you open the configuration window. When you exit this window your PAN ID will be restored to old value.

A standard configuration packet and its fields are explained in Figure 15. Its possible responses are also shown. The commands supported by this sensor are shown in Table 4, these can be used in the Parameters field of Payload section. The sensor responds to these commands with an acknowledgement if the process completed successfully or with an error if it failed to setup a parameter. The respective Data and Reserve section length and values are shown in Table 5 for the case of acknowledgement. In the case of error, the reserved section will be fixed and not used, while the Error number byte will determine the type of error returned. These errors are mentioned in Table 6.

Figure 15 depicts standard communication between Zigmo/Router and sensor. Sensor commands have variable length frames whereas responses received from sensor are fixed length. The 2 scenarios are also shown, where a command can result in an acknowledgement reception or an error reception at the Zigmo end.

 

Examples for setting parameters in configuration mode are shown in Appendix A.

Figure 15: Configuration mode communication
Table 4: Configuration Commands and their respective headers, sub command and Parameter field
Table 5: Acknowledgment data for various commands and the size of reserve section in each case
Table 6: Error numbers and their description

The UI, shown in Figure 16, can be used to configure the wireless sensor. At startup, it automatically changes the Zigmo PANID so that it can communicate with a sensor in configuration mode (indicated by the Led on the top right). Upon exit, the PANID of the Zigmo is restored to old value.

Individual settings can be programmed using the single command column.
The AUTO PROGRAMMING check option allows the user to setup multiple sensors with the same settings. In such a scenario, the user will be required to enable each check box for enabling a setting, enter the value for each setting if required and then check the auto programming check box. Afterwards, when a sensor is powered up and enters configuration mode, the PGM MODE DETECTED Led will flash and automatically program the checked settings. User can also program multiple settings by clicking the APPLY SELECTED button. Moreover, settings can be read using the individual buttons or all settings can be read using the READ ALL button.

 

Figure 16: Configuration mode User Interface

Appendix A

Configuration Commands

1. Set Broadcast Transmission

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 0100 0008 F4

2. Set ID and Delay

Command For COPY: 7E00 1710 0000 0000 0000 00FF FFFF FE00 00F7 0200 0008 0000 0004 EF

3. Set Destination Address

Command For COPY: 7E00 1710 0000 0000 0000 00FF FFFF FE00 00F7 0300 0008 1234 5678 DE

4. Set Power

Command For COPY: 7E00 1410 0000 0000 0000 00FF FFFF FE00 00F7 0400 0008 02EF

5. Set PANID

Command For COPY: 7E00 1510 0000 0000 0000 00FF FFFF FE00 00F7 0500 0008 7CDE 96

6. Set Retries

Command For COPY: 7E00 1410 0000 0000 0000 00FF FFFF FE00 00F7 0600 0008 03EC

7. Read Delay

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 1500 0008 E0

8. Read Power

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 1600 0008 DF

9. Read Retries

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 1700 0008 DE

10. Read Destination Address

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 1800 0008 DD

11. Read PANID

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F7 1900 0008 DC

12. Enable Encryption

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F2 0100 0008 F9

13. Disable Encryption

Command For COPY: 7E00 1310 0000 0000 0000 00FF FFFF FE00 00F2 0200 0008 F8

14. Set Encryption Key

Command For COPY: 7E00 2410 0000 0000 0000 00FF FFFF FE00 00F2 0300 0008 0011 2211 2211 2211 2233 4433 4433 4433 444F

Appendix B

Frame Checksum Calculation

In order to successfully communicate over the API protocol, checksum is of vital importance. The X-bee at either end will reject packets if the checksum is not matched. Checksum is also checked by the sensor controller and LabVIEW utility for added security.

For sending packets, checksum calculation works as follows

  1. Add all the bytes and keep the lower 8 bits of result (Excluding the frame delimiter and length)
  2. Subtract this value from 0xFF (hex)
  3. The resultant value is the checksum
  4. Append this byte at the end of the original packet for sending

Consider the example for the command Set Broadcast shown in Figure 19 in A APPENDIX and see that the calculated checksum matches with the checksum sent by the terminal/LabVIEW

Although checksum is matched by the X-bee itself, but for understanding follow these steps to match checksum at reception

  1. Add all the bytes including the received checksum (Exclude the frame delimiter and length)
  2. Keep only the last 8 bits
  3. If the result is 0xFF, the checksum is correct and the packet can be processed.

Consider the example of the command Set Broadcast shown in Figure 19 in A APPENDIX and see that the received packet checksum verifies since the result is 0xFF.