Hardware

Q: How many wireless sensors can be supported by the MonnitLink™ Wireless Gateway?

A: One MonnitLink™ Wireless Gateway can support up to 100 sensors. To expand the network beyond 100 sensors, simply add another MonnitLink™ Wireless Gateway to the network and continue expanding.

Q: What frequencies do the wireless sensors communicate on?

A: Monnit’s wireless sensor network currently operates in the ISM 900MHz (902-928MHz) band of frequencies. We support 250kbps data rate transfers in this frequency. (Coming soon in 2010: 433Mhz, and 868MHz)

Q: What should I do with my wireless sensor when the battery dies?

A: The average life span of a Monnit wireless sensor varies depending on how often the sensor is set-up to transmit to the MonnitLink™ Wireless Gateway.  That said, on average you should expect over 1 year of battery life from a sensor with a heartbeat of 1 hour. (Longer heartbeats increase battery life.) Once the battery has been depleted, you can change the battery by peeling the stickers away from the battery slot and battery removal hole then using the battery removal tool push the battery out and replace with a new CR2032 coin cell battery. We encourage you to recycle the old battery.

Q: Do you have a cellular gateway for your wireless sensor network?

A: Monnit currently offers a USB wireless gateway for our wireless sensor networks. Cellular and Ethernet gateways are in the works and will be available Spring 2011.

Q: Can I add additional sensors to the wireless sensor network at a later time?

A: Yes. You may expand your network as needed, up to 100 sensors per USB gateway. Upon reaching 100 sensors, we recommend you purchase an additional wireless gateway. This will lead to the best performance of your wireless sensor network.

Q: What do I need to have in my possession to run a Monnit wireless sensor network (WSN)?

A: To deploy a Monnit wireless sensor network, you will need a PC that is always powered on with an internet connection. Monnit wireless sensor kits will provides you with a MonnitLink™ USB Wireless Gateway, a variety of Monnit Wit™ Sensors, and a license to register the sensors on the iMonnit™ online wireless sensor monitoring system.

If you are not using a PC with MonnitLink™ USB Wireless Gateway, you can purchase a Monnit Ethernet or cellular gateway in addition to the kit which will allow your sensors to communicate with the iMonnit™ online wireless sensor monitoring system.

Q: Should I expect interference from other wireless networks (WiFi, walkie talkies, cordless phones, cellular phones, radios, etc.) operating in the vicinity of my Monnit wireless sensor network (WSN)?

A: No. Monnit's wireless sensors currently operate in the 900Mhz ISM band. Most wireless sensors today operate in the crowded, 2.4Ghz space where cell phone, WiFi networks, wireless telephones, and many wireless accessories for networks and PCs operate.

Monnit chose the 900Mhz frequency for its performance characteristics (much better range through obstacles than 2.4Ghz) and "openness" of the frequency. Operating at 900Mhz limits the ability to deploy sensors to a specific region (North America only).

The chipset used by Monnit for our wireless sensors also supports 868MHz as well as 433MHz. Support for international markets will utilize these two frequencies for best performance.

Q: Do the gateways look for a clear RF channel when it is powered up? Can it switch channels if noise or interference is high?

A: During testing of sensor networks prior to shipping of the product, the networks are formed and the gateways choose a channel to transmit on. When you receive the product, that channel stays constant until reset by the user.

If you want to have the gateway search for the most clear channel in your environment, you will need to follow these steps:

For iMonnit users:
1. Start the iMonnit gateway software
2. Insert the USB dongle and wait for the network to go active
3. Select "Reset Network" within the gateway software and wait for 30 seconds
4. One new network has reformed, begin putting the batteries in the sensors

For Monnit Express users:
1. Start the Monnit Express software
2. Insert the USB dongle and wait for the network to go active
3. Go to the pull down menu titled "File" and select "Reset Network," wait for 30 seconds
4. One new network has reformed, begin putting the batteries in the sensors

Your sensor network is now operating on the most friendly RF channel available in your area.

Q: What are the voltage input requirements for the OEM/RF wireless sensor circuit boards?

A: We support V in 2 - 3.6 VDC max.

Q: What is the power draw of a wireless sensor?

A: In sleep mode the sensor consumes .5µ Amps and during transmit the sensor consumes 35 mA.

Q: What is the average life span of the battery in the wireless sensors?

A: The life span of the battery is dependent on a number of factors: how long the sensor is "sleeping" (a sensor will draw nominal power during sleep state ~.5µ Amps); how long it takes the sensor to reach its awake state, and how long it is on, using the radio to transmit the data to the MonnitLink™ Wireless Gateway.

Monnit estimates through normal usage a sensor in the field should last over 1 year at a 1 hour heartbeat before it needs to be replaced.

Q: What happens to my wireless sensor network if the PC being used as the application host goes into sleep mode or is powered off for some reason?

A: If the MonnitLink™ Wireless Gateway is unable to receive transmissions from the sensors due to the PC being off, or the gateway not being installed, the sensors will continue to try and link with the gateway (two times by default). If it is unable to link to the gateway it will enter “link mode” where it will search for a nearby gateway. If no gateway is found, the sensor enters "power save" mode, and will sleep for two hours before entering link mode again, and scanning all available channels for a gateway. This process will continue until the sensors find a gateway to communicate with.

Note: While the gateway is off, no data is being collected and no notifications can be transmitted.

Q: Does the USB MonnitLink™ Wireless Gateway need to be plugged directly into the computer, or can I plug it into a USB port expander?

A: If you are using an unpowered USB port expander/hub, the MonnitLink™ USB Gateway will not operate properly. To insure best performance of the Monnit Sensor Network, plug the USB gateway into a powered port expander, or best yet is to plug the USB gateway directly into a USB port on your computer.

Q: How many hops can your wireless sensor network manage?

A: Monnit’s wireless sensor networks are configured to allow one hop. That is: Monnit WIT™ Wireless Sensor <-> Monnit Wireless Repeater <-> MonnitLink™ Wireless Gateway.

You can use more than one repeater on a single sensor network, however the repeaters will not not hop between each other at this time. Each repeater can communicate to any wireless sensors within range, and the wireless gateway (not other repeaters).

Q: What are the size of the data packets being transmitted by the sensors to the gateway?

A: The application data is 18 bytes in length and the total TX packet size is 40 bytes.

Q: How do I mount the wireless sensors for my particular application?

A: Monnit has provided a number of mounting options for the sensor technology. In the deployment kits we have included screws and double-sided tape. These options should allow you to mount the hardware to most any type of material.

Q: My temperature sensor is giving me a reading of -1767.8F (-999.9C), what does this mean?

A: A reading of -1767.8F signifies that the thermistor wires have broken or the battery has not been fully inserted causing a short between the thermistor leads on the sensor board. If this happens; try removing the battery, wait 45 seconds then re-insert the battery making sure to push the battery all the way to the back of the sensor housing. When the sensor comes back online check the reading to see if it has been corrected. If the problem persists you will need to contact Monnit customer support at 801-561-5555 for more information.

Q: How do my wireless sensors connect to the monitoring software on the internet?

A: Each Monnit WIT™ wireless sensor comes ready to connect to the MonnitLink™ Wireless Gateway upon power up. Make sure that the USB Driver has been installed and the Monnit Gateway Software is installed and running, then simply insert the MonnitLink™ USB gateway into the PC. Once the gateway establishes a connection with the iMonnit™ online wireless sensor monitoring system and registers itself with the Monnit servers, simply insert the batteries into their holder on each sensor. The sensor will power up and connect to the MonnitLink™ Wireless Gateway and register with iMonnit™, assigning each sensor its own unique id number.

Q: Do you offer any other types of wireless gateways besides just the USB dongle for your wireless sensor networks (WSN)?

A: At this time Monnit only offers a USB version of our MonnitLink™ Wireless Gateway. In mid 2010 Monnit will offer support via cellular and Ethernet protocols.

Q: How sensitive is the Monnit wireless temperature sensor?

A: The thermal range of Monnit's wireless temperature sensor is -50°C to 150°C (-58°F to 302°F). It's accuracy is +/- 2°C (+/-3.6°F) with single point calibration. This sensor is suitable for most commercial and consumer applications.

Q: Will a wireless sensor notify me when I need to change the battery?

A: Each time the sensor transmits data to the MonnitLink™ Wireless Gateway, the sensor reports the batteries life as a percentage of the life left. It is not an exact reading, but will provide you with enough information to know when the battery is about to expire.

Software

Q: Why can't I edit my sensor settings?

A: Sensor Availability
Because Monnit sensors are battery powered it is critical that customers leave the radio inactive between transmissions to conserve power. A CR2032 battery that can last for a multiple of years transmits a signal every hour or two, thereby conserving power and in return preserves battery life. (Monnit's recommended heartbeat is not more than once every hour.)

If transmissions from the sensor are increased and left listening for continual communication, the battery life is impacted harshly (maximum battery life could be as little as approx. 2 hours). This forces iMonnit to pass sensor updates to the sensor only after the sensor has turned on its radio and listens for an acknowledgment. During the acknowledgment, iMonnit can notify the sensor that the database (DB) has a configuration update and from there the network can communicate the update to the sensor. At this point the sensor acknowledges the configuration update and iMonnit marks the transaction complete (removing the pending transaction flag).

Gateway Lag:
Similar to the sensors, iMonnit can't instantly initiate communication to the gateway. The reason is many firewalls and security measures keep intruders from accessing the customer's network. Out of the box the gateway is configured to communicate with iMonnit once every five minutes. (It uses the same communication protocol as your web browser does while communicating to your bank.)

Because of the five minute heartbeat of the gateway there is a lag (delay time) between the time the user saves the configuration settings on Monnit's server and the time the gateway checks in to receive the updates. Only after the gateway has acknowledged the updates the sensor checks in and receives them.

Network Stability:
During pending transactions it is impossible for iMonnit to know which stage of the process the configuration is in. For example, if a user has set a configuration change to set the sensor's new heartbeat to 30 minutes, the gateway received the request while the sensor still hasn't.

There are certainly other network stability cases such as if iMonnit modified the configuration to a 3 hour heartbeat to conserve battery life, the following could occur to cause network instability.

The 3 hour change is observed in iMonnit, from here the gateway is ready to talk to the sensor and inform it that the heartbeat should be 30 minutes now. When the sensor checks in and receives the configuration change it will receive the 30 minute heartbeat rather than the 3 hour heartbeat. If the sensor was to communicate up to the server that it has successfully updated its configuration, iMonnit must assume it has been updated to 3 hours and marks the transaction as complete. This is the reason Monnit marks transactions that require communication with the sensor as "Pending".

To be able to update sensor configurations the user needs to make sure the sensor is communicating well to iMonnit and wait until the pending configuration completes.

Q: What energy levels does your battery graphic in software represent?

A: Monnit offers two sensor products with different battery options. The Monnit WIT is our cheapest, and most common sensor line and is powered by a single CR2032 3.0V coin cell battery. The Monnit WIT² is powered by two 1.5V AA batteries and provides the user with a greatly extended battery life.

The battery graphic in Monnit's software solutions (iMonnit, Monnit Express and Monnit Enterprise) is represented by five different images:
• Above 75% it shows Full
• Above 50% it shows Three Quarters
• Above 25% it shows Half
• Above 10% it shows One Quarter
• Above 0% it shows red
• At or below 0% it shows Empty

The percentages are configured per the following table:



Monnit uses linear interpolation for all values between the given points. For example, a battery voltage of 2.95 is between 2.9 and 3.0. The battery percent is half way between 75% and 100% (or 87.5%) so the display will be rounded to 88%.

Because the power reservoir is small in the CR2032, the voltage can fluctuate between reads. This can cause the reading to change from 50% to 0% by only having a .15V drop at the time of the battery read. For example, if the network encounters any interference and the sensor has to transmit more than once, the battery will display lower than subsequent readings that don't have to send retries.

A benefit to AA batteries will show a much smoother curve as the batteries drain due to the larger power reservoir.

Q: How do I turn OFF/ON email and text notifications for my sensor network?

A: iMonnit has a global feature so you can stop notifications from sending emails and text messages to your devices. To turn this feature on and off, do the following:

1. Login to your account
2. Once logged in, from the top pull-down menu, find and select "My Account"
3. On the left hand side, find "Sensor Networks" and select the edit pencil next to the network for which
you would like to the notifications turned off
4. The second feature down is titled "Send notifications for this Network"
5. If notifications are being sent, deselect the check box. If notifications are NOT being sent, select the
check box.
6. Click "Save"

Q: How do I get my sensors to stop sending alerts to my email or phone when they are inactive?

A: Logged in as the administrator, you can halt the alerts by doing the following:

1. Select the sensor you wish to edit (it could be named "Temperature 1" or you may have renamed it to
something else).
2. Click on the edit box next to the sensor name (looks like a pencil).
3. You will see the "Basic Sensor Configuration. Below it is an underlined "Advanced Configuration" link. Select it.
4. You are now in the Advanced Sensor Configuration Screen. Select the field titled "Inactivity Alert (Minutes)."
5. Insert a "0" (zero) into the field.
6. Click "Save."
7. Your sensor will now stop sending you notifications that the sensor is inactive.

You can also do a mass configuration of the network of this feature by doing the following:

1. At the bottom of your sensor list is a link titled "Configure Multiple Sensors."
2. Click on the link.
3. Check all of the sensors you wish to include in the configuration.
4. In the "Inactivity Alert (Minutes)" field, insert a "0" (zero) into the field.
5. Click "Save."

If you have additional questions regarding this feature, please email us at support@monnit.com.

Q: Why do I see two messages of the same type in a row from one of my sensors?

A: One of the strengths of the Monnit protocol is that the sensors can both transmit and receive. After a sensor transmits its data it waits to hear an acknowlegement back from the gateway that the sensor data was received. If the sensor does not hear back from the gateway in a certain period of time it will retransmit the data. By default the sensor will resend up to three times if needed before it goes back to sleep.

The most likely cause of the duplicate data is that the sensor sent the data and the gateway received it, but when the gateway sent the acknowledgment back to the sensor, the packet was lost. The sensor resent the data to the gateway, then the second acknowledgement made it to the sensor and the sensor went back to sleep (Turned off its radio).

There are several reasons that packets can be lost. The most common are weak signal strength or another sensor (or other equipment in the 900Mhz range) transmitting at the same time as the wireless gateway.

Q: What happens to the data from my wireless sensor network if the power to my MonnitLink™ Wireless Gateway is off or disrupted?

A: While the gateway is off, no data is being collected and no notifications can be transmitted by the sensor. In short, the data is being discarded by the sensor.

If the MonnitLink™ Wireless Gateway is unable to receive transmissions from the sensors due to the PC being off, or the gateway not being installed, the sensors will continue to try and link with the gateway (two times by default). If it is unable to link to gateway it will disassociate itself from the gateway and enter “link mode” where it will try to find a gateway nearby.

Q: How do I make changes to the wireless sensor parameters?

A: Configuration data is entered into pages from the web application used by the administrator and stored in the database on the server.  At regular intervals the MonnitLink™ Wireless Gateway requests configuration data from the server and stores this data locally. Independent of this sequence, sensors wake up and start communicating with the gateway. If there is data for the sensor stored in the MonnitLink™ Wireless Gateway then the data is transferred to the sensor. After the data, if any, is transferred, the sensor goes back into sleep mode.

Q: Can I export sensor data from your database to my own application?

A: Yes you can! An API exists which allows you to make calls from our DB by your application. You can access the API at https://www.imonnit.com/api.

In addition to the API, you can have Monnit push the sensor readings from iMonnit to your database with our external configuration tool. This tool allows you to pass data from your wireless sensor network devices to another service in real time. This is done by coding the data into a URL query, then sending the data via HTTP get request at the time data is received. There is an extensive list of parameters that can be passed, allowing you to send detailed information about both the data and the sensor. For information on iMonnit's Push API click here.

Q: What does the "x" mean next to my sensor in iMonnit?

A: Sensor Availability
Because Monnit sensors are battery powered it is critical that customers leave the radio inactive between transmissions to conserve power. A CR2032 battery that can last for a multiple of years transmits a signal every hour or two, thereby conserving power and in return preserves battery life. (Monnit's recommended heartbeat is not more than once every hour.)

If transmissions from the sensor are increased and left listening for continual communication, the battery life is impacted harshly (maximum battery life could be as little as approx. 2 hours). This forces iMonnit to pass sensor updates to the sensor only after the sensor has turned on its radio and listens for an acknowledgment. During the acknowledgment, iMonnit can notify the sensor that the database (DB) has a configuration update and from there the network can communicate the update to the sensor. At this point the sensor acknowledges the configuration update and iMonnit marks the transaction complete (removing the pending transaction flag).

Gateway Lag:
Similar to the sensors, iMonnit can't instantly initiate communication to the gateway. The reason is many firewalls and security measures keep intruders from accessing the customer's network. Out of the box the gateway is configured to communicate with iMonnit once every five minutes. (It uses the same communication protocol as your web browser does while communicating to your bank.)

Because of the five minute heartbeat of the gateway there is a lag (delay time) between the time the user saves the configuration settings on Monnit's server and the time the gateway checks in to receive the updates. Only after the gateway has acknowledged the updates the sensor checks in and receives them.

Network Stability:
During pending transactions it is impossible for iMonnit to know which stage of the process the configuration is in. For example, if a user has set a configuration change to set the sensor's new heartbeat to 30 minutes, the gateway received the request while the sensor still hasn't.

There are certainly other network stability cases such as if iMonnit modified the configuration to a 3 hour heartbeat to conserve battery life, the following could occur to cause network instability.

The 3 hour change is observed in iMonnit, from here the gateway is ready to talk to the sensor and inform it that the heartbeat should be 30 minutes now. When the sensor checks in and receives the configuration change it will receive the 30 minute heartbeat rather than the 3 hour heartbeat. If the sensor was to communicate up to the server that it has successfully updated its configuration, iMonnit must assume it has been updated to 3 hours and marks the transaction as complete. This is the reason Monnit marks transactions that require communication with the sensor as "Pending".

To be able to update sensor configurations the user needs to make sure the sensor is communicating well to iMonnit and wait until the pending configuration completes.

Q: What happens if I push "Reset Network" in the Monnit Gateway Application?

A: Pressing the "Reset Network" button in the Monnit Gateway application will release the USB Gateway's wireless channel and re-scan for the clearest available wireless channel. On each sensor's next heartbeat, it will enter link mode and rescan to find the Gateway. It is recommended to reset your network if any of your sensors are have problems checking in regulary.

Q: How secure are the communications on the wireless network?

A: Monnit uses the same encryption methods used by websites to transmit financial data.  Secure socket layer (SSL) protocol is employed with 256-bit data encryption making data hosted on your network secure.

Q: What software do I need to install to initiate the wireless sensor network?

A: In order to use a Monnit Wireless Sensor network you will need to download and install the USB drivers for the MonnitLink™ Wireless Gateway and the Monnit Gateway Software which will allow your sensors to communicate with the online system. No additional software or drivers are required.

Q: Is it possible to control a remote device using Monnit wireless sensors?

A: Monnit WIT™ Wireless Sensors do not currently support control. This may be included in future versions of the product.

General Questions

Q: Can I use a Monnit Link USB dongle with a laptop and aircard?

A:Yes, we have several customers currently using aircards to connect their sensors to the iMonnit™ online wireless sensor monitoring system. However, the gateway is not a data logger and if communications are interrupted data can be lost until the network connection is restored. To aid in this, we have added a 15 second retry to all messages. However, if the connection is still not available after 15 seconds, the data will be lost.

Q: How does the wireless sensor network notify the user there is an incident that requires an action?

A: The iMonnit™ online wireless sensor monitoring system notifies the designated contacts(s) via SMS (text message), e-mail, or voice mail.

During the set-up process through your iMonnit online portal, the administrator can program in cell phone numbers and e-mails of the individuals requiring notification, establishing the contact criteria for each of the above three methods of communication.

Q: How much will I be charged for text message notifications?

A: You will not be charged by Monnit for text messages issued by the Monnit Sensor Network. The text messages you receive from Monnit are routed through your cellular provider. Thus, any text message notifications you set-up to receive from Monnit’s notification service are covered under your text message plan through ATT™, Sprint™, Verizon™, T-Mobile™, et al. If you do not subscribe to a text plan through your cellular carrier, you will be charged their standard rate for receiving a text message.

Q: Why is there a delay in my sensor notifications?

A: Having a delay in notifications is not typical however there are some things that can cause this. Both Email notifications and SMS notifications are sent over SMTP. Our SMTP relay server is configured to ensure timely delivery of your notifications.

If the receiving server (your mobile phone company in the case or your SMS (text) notifications) is too busy or down for maintenance, etc. The SMTP Relay will try to re-send the message again, several times within the first hour. Then it will attempt to deliver every 4 hours until the receiving server is ready to receive for up to 2 days. After two days it is assumed the notification must have a bad address and it is discarded.

Q: Will I need to buy or replace the batteries for my wireless sensors?

A: Batteries are included with the purchase of every wireless sensor that ships from Monnit. Under normal operating conditions a sensor in your Monnit wireless sensor network (WSN) will last for 3,000 transmissions (2-4 years with a 1+ hour heartbeat.)

Q: Environmental Attributes That May Affect RF Range of Sensors

A: Wireless sensors transmit their data using wireless radios, and as such are subject to the same environmental limitations found in all wireless communications.  Elements that effect radio transmission are severe inclement weather, trees, heavily constructed walls (cement, cinder block), sheet metal, wall board, wood, tile, buildings, vehicles, etc.  Unless you have direct line of sight, every obstruction impedes wireless transmissions, even the human body.

In short, there are four factors to keep in mind for the health of your wireless sensor network and maintaining its peak performance:

• distance from sensor-to-sensor and the wireless gateway
• power output of the radio
• data rate transmission
• frequency of the radio link

Q: How To Orient Your Antennas for Optimal Range

A: View this article from our Wise Guys support area to learn how to orient antennas for optimal range and performance. « View Article

Q: How do I pay for my products?

A: Monnit has a variety of ways you can pay for your products.  Orders can be placed via credit card using our online store or you can contact a Monnit sales representative for personal assistance.

Q: What is your return policy?

A: In order to return your product for an exchange or refund, you must first contact your Monnit sales representative and request a return merchandise authorization (RMA) number.  You can reach your sales representative at 801-561-5555.

No packages will be accepted without the RMA number clearly marked on the outside of the package. After inspecting and testing, we will return your product, or its replacement using the same shipping method used to ship the product to Monnit within 30 days. In your package, please include a daytime telephone number and a brief explanation of the problem.