Knowledge Base / Protocols / DeviceNet

DNspector Frequently Asked Questions

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1.       What is DNspector and why should I consider purchasing it?

 DNspector was created to provide a low cost CAN monitor, primarily used by engineers and installation technicians to allow viewing of the packets on a CANbus network. DNspector may be set up for DeviceNet, J1939, or CAN Open format.  DNspector is designed to handle the 29-bit extended CAN packets.  With unlimited logging, message sending capability, and an easy to read DeviceNet Interpreter built in, DNspector can be plugged into any CAN network using an inexpensive dongle which communicates through a USB port on any computer that has the DNspector software installed.

2.       What are the key features of DNspector?

  • Full interpreter for DeviceNet messages.
  • Numeric display available in both DeviceNet and J1939 network mode.
  • No interference with network under surveillance.
  • Rockwell Point I/O compatible.
  • Unlimited Logging capability limited only by available hard disk space.
  • Capture feature for temporary review of messages.
  • Easy to use Message Sending dialog. Allows fragmented message generation using a special Dialog, which can be saved and loaded from a file.
  • Browse Network and get identity information with connection sizes.
  • Network to be monitored may be predefined using EDS files.  Poll sizes can be set in the Network Assign dialog.  Configuration stored in the Net Configuration Files (.ncf) files on your local drive.
  • Extensive message filtering for logging, capture, and searching.  Easy to use Filter Editor that generates inclusive and exclusive filters.
  • Log and Capture search capability using the above filters.
  • Predefined CAN selectable baud rates, including DeviceNet baud rates:  125k, 250k, and 500k, as well as J1939 baud rates of 10k, 20k, 40k, 50k and 100k.
  • Customized baud rate selection using BTR0 and BTR1
  • Allows customizable Message Delays, allowing for monitoring of slower devices or networks.   

3.       Where is the DNspector User’s Manual located?

For DNspector User information please see the Menu Bar HELP item in the main application.  Please see the Product Data Sheet and the Quick Start Guide for additional information.

4.       How do I begin to use DNspector?

DNspector must be installed on a computer that has an optical disk drive, and a USB port running Windows XP, Windows 2000 or Vista.  The USB dongle driver software is included on the installations disk, and must be installed 

NOTE: This has not been thoroughly tested on Windows 7/64, or Windows 7/x86 or above.

5.       How do I Install DNspector?

  1. Insert the install DNspector Installation disk.  However, DO NOT insert the dongle yet.
  2. The DNspector software should automatically launch.  Follow the onscrren instructions of the installation software.
  3. After the DNspector software has been installed, insert the USB dongle into a free USB port on the PC.
  4. When the computer detects the new hardware, it will ask for the source of the dongle drivers. Select the Find Drivers option.  The system will find the drivers on the DNspector install disk.  Follow the onscreen instructions to install the USB driver Software.  You may need to get your IT department involved in this phase, and the drivers will almost certainly ask for permission to install drivers.  On some systems, this may happen twice.
  5. Once the driver install is done, keep the Dongle inserted the same USB port you installed it in, and you can now start DNspector.

6.       Why does the dongle not connect?

DNspector expects a network connection which is terminated correctly and has at least one working device on the network.  Also, if you attempt to browse the network, and no device responds with an acknowledgement pulse, the dongle will only output messages until its buffer overflows. DNspector is then forced to terminate the connection attempt. Be sure to have the baud rate set correctly for the device on the network.


7.       Why is the Browse Button disabled while I am monitoring an active network?

When you are monitoring a live network, the master has connected with all the devices on line and therefore has exclusive access with all devices. DNspector is made to NOT interfere with the network while in operation.  So, to browse the network, the master scanner of the network must be disconnected or disabled.


8.       Why does the Live Screen display nearly 2000 messages, then just stop?

Due to limitations of the control used to display the live data on the network, only about 2000 messages can be received without any chance of missing messages. If an on going display of live messages is required, you may set the Live Screen to Auto-Display by going to the menu and selecting Network, then Auto Reset Live Screen. This displays 2000 messages, then clears the control and displays 2000 more messages without losing ANY messages.  Once the message limit is reached, it will clear the control, and display the batch of messages.  This will repeat indefinitely, until you disable the Live Screen.


9.       What does browsing the network do for me?

Browsing the network allows you to see what devices are online and their Mac Address actually is. It also brings in the Identity Object's content. This may be seen by going to the menu and selecting Network, then select the Net Configuration View menu item. It also allows DNspector to get the active Producer/Consumer sizes thus allowing DNspector to know the poll sizes.  This allow the fragmented messages to be correctly notated in the frag column.


10.   What is the EDS system?

EDS stands for "Electronic Data Sheet", and is used extensively in the Automation/PLC Industry to describe everything anyone would want to know about the device.  DNspector has a built in EDS library.  Selecting the EDS menu item, then Config Network, DNspector will display a split screen that allows you to load EDS files into DNspector's EDS library. Once the EDS files are loaded, you can drag the EDS identifier from the right half of the screen to the left half, into the device MacId slot and drop it. This allows you to pre-setup a network so that onsite browsing is unnecessary. You can also edit the poll sizes to conform with the networks polling configuration.


11.   What Does Rockwell Point I/O compatible mean?

Rockwell made its Point I/O devices with a 2 byte instance value instead of only a single byte.  So "normal" systems might have have trouble working with them, while DNspector can detect a Point I/O device and alter its messages so that THAT device can talk with them.


12.   Why is there a Master MacId and a Monitor MacId?

This allows DNspector to know what MacId is used as a master, and allows the operator to know what messages have been sent by DNspector. It is NOT advisable to use the master's MacId, due to the possibility of introducing conflicting messages on the network that contain the same source MacId.


13.   What is the Function of the Special Connect button?

While DNspector has quite a few available baud rates that can be used by simply selecting it from the Network Setup dialog.  In some instances, odd, or non-standard baud rates may be necessary. The BTR values must be computed using the formula for NXP xxx-1000 running at 12mhz.


14.   What is the difference between Logging and Capturing?

Capturing is done to a predefined file, which is hidden from normal user access. You may capture messages for any length of time required.  While you may view it, and print it, you CANNOT save it as a file.

Logging allows you to save as much as your disk drive can hold, since DNspector uses multiple files to store the data. Since the disk operating system marks the create date and time, you always know when the file was started. The messages are stored with the time of reception into the user named files. A maximum of three million messages are stored in a file, and DNspector will automatically rotate the files, rather than just creating one large file.  DNspector, however, will read these files as if it were one very large file.  A logging session can  can go for more than 30 days at a time, while maintaining a reso

lution down to the millisecond.  You can adjust the size of the logging files under the File Menu and the Setup File Size option.  3 million messages per file is the largest value permitted.