Troubleshooting Communication Problems with the FieldPoint Ethernet Network Modules

Publish Date: Mar 23, 2012 | 30 Ratings | 3.27 out of 5 |  PDF

Overview

This document presents the most common problems encountered when using FieldPoint Ethernet Network Modules (FP-1600, FP-2000, and FP-2010). Before you begin the troubleshooting steps in the following sections, National Instruments recommends verifying correct configuration of the FieldPoint Ethernet Network Module in FieldPoint Explorer by building a new .iak file. See our FieldPoint Support page on FieldPoint Ethernet Network Module Configuration for a step-by-step guide to this procedure.

Table of Contents

  1. Incorrect Subnet Mask Settings
  2. Incorrect Ethernet Hub Configuration
  3. Duplicate IP Address
  4. Incorrect Ethernet Cable
  5. Operation Outside of Specified Temperature Range
  6. FieldPoint Explorer and Firmware Versions
  7. Operation with Insufficient Power Supply
  8. Diagnostic Check
  9. Resetting your FieldPoint Ethernet Network Module Configuration

1. Incorrect Subnet Mask Settings

Most Common Symptom: The FieldPoint Ethernet Network Module does not appear in FieldPoint Explorer
When using the Browse feature of FieldPoint Explorer, a communication method called Broadcast UDP is used to locate FieldPoint Ethernet Network Modules. However, in nearly all network configurations, network routers are configured to filter UDP broadcast packets. This blocks detection of modules across different network subnets. Therefore, both the FieldPoint Ethernet Network Module and the computer accessing the FieldPoint Ethernet Network Module must be connected on the same subnet for the Browse feature of FieldPoint Explorer to detect the FieldPoint Ethernet Network Module. Even if you cannot Browse to the FieldPoint Ethernet Network Module, you can still configure and communicate with the FieldPoint Ethernet Network Module in FieldPoint Explorer by manually entering the IP Address of the module. If communication with the FieldPoint Ethernet Network Module cannot be established through the IP Address, National Instruments recommends resetting the FieldPoint Ethernet Network Module. For the procedure to reset the FieldPoint Ethernet Network Module, please see the Resetting FieldPoint Ethernet Network Modules section.

If the FieldPoint Ethernet Network Module is in the "unconfigured" state from either a reset or before first use, then the Browse feature of FieldPoint Explorer must be used to configure the module. Therefore, the unconfigured FieldPoint Ethernet Network Module must be physically connected to the same subnet as the computer used to configure the module. Typically, this means that both the computer and the FieldPoint Ethernet Network Module must be connected to hubs that are on the same subnet. Contact your network administrator to determine which Ethernet ports of your network hubs are on the same subnet.

The subnet is determined by performing a logical AND on the IP address and subnet mask. For example, a system with an IP address of 10.10.10.10 and a subnet mask of 255.255.255.0 is on the subnet of 10.10.10.x. Thus, all systems with an IP address of 10.10.10.x and a subnet mask of 255.255.255.0 are considered to be on the same subnet. Likewise, if the systems had a subnet mask of 255.255.0.0, all systems with an IP of 10.10.x.x would be considered part of the same subnet. To determine the IP address and subnet mask of your computer, run winipcfg.exe (Win9x) or ipconfig.exe (NT/2000) from the MS-Dos Prompt to retrieve information similar the information in the following dialog box:



Figure 1. IP Configuration Dialog Box


In the IP Configuration dialog box shown above, the IP address of this computer is 130.164.58.131, and the subnet mask is 255.255.255.0. Therefore, to use the Browse feature of FieldPoint Explorer to detect a FieldPoint Ethernet Network Module module, the FieldPoint Ethernet Network Module must have an IP address of the form 130.164.58.x and subnet mask 255.255.255.0. If the FieldPoint Ethernet Network Module does not have this configuration, type the IP address of the FieldPoint Ethernet Network Module (if it is already configured) into FieldPoint Explorer to communicate with the module.

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2. Incorrect Ethernet Hub Configuration


Most Common Symptom: The FieldPoint Ethernet Network Module does not appear in FieldPoint Explorer
Inability to communicate with a FieldPoint Ethernet Network Module module is often caused by incorrect configuration of an Ethernet hub or router. The most direct method of verifying proper configuration of a hub and router is to connect a computer to the same port where the FieldPoint Ethernet Network Module will be connected. Then, configure the computer to have the same static IP address and subnet mask that you wish to assign to the FieldPoint Ethernet Network Module. To put it another way, instead of trying to connect to a FieldPoint Ethernet Network Module on the port, try to connect to another computer on the port. The advantage of this approach is that network administrators are very skilled at troubleshooting network problems with computers, but might not have experience troubleshooting network problems with FieldPoint Ethernet Network Modules. However, since a FieldPoint Ethernet Network Module and a computer with a static IP address appear the same to a network, National Instruments recommends that proper operation of the FieldPoint Ethernet Network Module’s physical connection to the network be verified using a connection to a computer if improper hub configuration is suspected.

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3. Duplicate IP Address


Most Common Symptom: Intermittent Loss of Communication
Each device on a subnet must have a unique IP Address. If two devices on the same subnet have the same IP Address, then various communication problems will result. These problems can include the FieldPoint Ethernet Network Module not being detected by FieldPoint Explorer, intermittent communication loss with the FieldPoint Ethernet Network Module, and intermittent errors or alarms from programs communicating with the FieldPoint Ethernet Network Module. The most common cause of this situation is when a new computer is added to the network, and the Network Administrator unknowingly assigns the new system the same IP address as the FieldPoint Ethernet Network Module. For this reason, National Instruments recommends that you contact your network administrator before assigning a static IP address to the FieldPoint Ethernet Network Module.

To check if a duplicate IP address is the cause of communication problems, perform the following procedure. First, disconnect the FieldPoint Ethernet Network Module from the network by removing the Ethernet cable or cutting power. Then, enter the Windows ping command from the MS-DOS prompt to ping the IP address of the FieldPoint Ethernet Network Module. The example below pings the IP address 130.164.58.41. If you receive Reply from responses such as the example below, then a device was found at that IP address. If a device is not found at the IP address, then the response request timed out is received. If a response is received from the FieldPoint Ethernet Network Module’s IP Address when the FieldPoint Ethernet Network Module is not connected, then another device is using the same IP address. Note that the second device on the IP address might not be running when you do the ping test. Check with the network administrator or run the test at different times if you suspect a duplicate IP address assignment.



Figure 2. Ping Test

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4. Incorrect Ethernet Cable

Most Common Symptom: The FieldPoint Ethernet Network Module does not appear in FieldPoint Explorer
When connecting the FieldPoint Ethernet Network Module to a switch or a hub on a network, use a standard Category 5 Ethernet cable. However, if you are connecting the FieldPoint Ethernet Network Module directly to the Network Interface Card (NIC) in your computer, use a special crossover cable. One common indication that the FieldPoint Ethernet Network Module is connected with the incorrect cable is that the LINK LED does not light on the FieldPoint Ethernet Network Module. However, there are cases where the LINK light can be on even with the incorrect cable. Typically, you cannot determine if a cable is straight-wired or crossover by cable color or by the label. However, most Ethernet cables have clear plastic connectors that allow you to see the 8 internal wires. If the green and orange wires are crossed between one end and the other, then the cable is a crossover cable. But if the green and orange wires are in the same relative positions on both ends of the cable, it is a normal cable. Also be aware that in some cases a normal cable is made to crossover with an extra adapter at one of the ends. For more information on Ethernet cable wiring connections, refer to the Cabling section in chapter 2 of the FP-1600 User Manual.

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5. Operation Outside of Specified Temperature Range


Most Common Symptom: Intermittent Loss of Communication
The operating temperature of the FieldPoint Ethernet Network Module is 0 to +55 °C, (+32 to +131 °F). Operating the FieldPoint Ethernet Network Module outside of the specified temperature range might result in a loss of network communication. Additionally, application programs might report errors such as Cannot connect to process and Timeout Period Expired. If this is the problem, power-cycling the module will temporarily clear the problem, but the problem might re-appear later. However, because the module is operating outside of specifications, the exact failure mode cannot be guaranteed. One possible situation that can result in over-temperature operation is placing the FieldPoint Ethernet Network Module in an enclosure with high power modules and no ventilation. If over-temperature operation is suspected, check the operating temperature of the FieldPoint Ethernet Network Module with a thermometer, thermocouple, or other type of temperature measurement device. Typically, ventilation fans can be added to FieldPoint module enclosures to keep the operating temperature within specifications.

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6. FieldPoint Explorer and Firmware Versions


Most Common Symptom: Intermittent Loss of Communication
National Instruments recommends that at a minimum, firmware revision 0200 be used with the FieldPoint Ethernet Network Module, but it is a good idea to always use the latest available firmware. . For instructions on how to check the current firmware revision, please see our KnowledgeBase entry on Determining the Firmware Revision of Network Modules. To update to the most current release of the FieldPoint Ethernet Network Module firmware, please see our KnoweldgeBase entry on How Do I Update the Firmware of an FieldPoint Ethernet Network Module?. Additionally, National Instruments recommends FieldPoint Explorer version 2.0.1 (or higher) for the most robust communication under various network fault conditions. Please visit our Drivers and Updates Library to download the current version of FieldPoint Explorer.

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7. Operation with Insufficient Power Supply


Most Common Symptom: Intermittent Loss of Communication
Under certain brown-out type conditions, the processor goes into a halt state that is not cleared until power is removed and re-applied to the module. This can happen if the power supply voltage drops below 11 V (the minimum specified voltage), but briefly remains in a range of ~0.7-10.9 V. However, because the module is operating outside of the specified power supply range, the exact failure mode cannot be guaranteed. To determine if you are suffering from an insufficient power supply, connect a multimeter or oscilloscope to the V and C terminals of the FieldPoint Ethernet Network Module. Verify that the power supply voltage is above 11 volts at all times and under all operating conditions. For example, if the FieldPoint Ethernet Network Module power supply is also used to drive other devices, test the power supply voltage when those devices are active and pulling maximum current.

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8. Diagnostic Check


Most Common Symptom: Intermittent Loss of Communication
A very small percentage of FP-1600 revision A and B modules had a manufacturing defect that could potentially cause intermittent loss of communication. Additionally, application programs might report errors such as Cannot connect to process and Timeout Period Expired. If this is the problem, power-cycling the module will temporarily clear the problem, but the problem might re-appear later. The revision of a FP-1600 module can be determined by reading the label on the underside of the FP-1600. The label will list an assembly number of the format 185690x-01, where x is the revision letter. To determine if a revision A or B module is suffering from the defect, please download the FieldPoint Ethernet Network Module Diagnostic Utility. If the test utility determines that the module suffers from the defect, please contact National Instruments Technical Support for a RMA number and upgrade per Engineering Change Order (ECO) 13425.

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9. Resetting your FieldPoint Ethernet Network Module Configuration


Since it is possible to configure the Ethernet settings of the FieldPoint Ethernet Network Module so that the device cannot communicate with the network, National Instruments recommends resetting the FieldPoint Ethernet Network Module when troubleshooting communication problems. For instructions on how to reset a 2000/2010 module please refer to the FP-200/2010 User Manual.

The following information is excerpted from the FP-1600 User Manual, Appendix A, “Resetting the FP-1600”. For more information and the full text of the instructions, please refer to the FP-1600 User Manual.



Figure 3. Underside view of the FP-1600 showing the Reset Switch


To reset your FP-1600, follow these steps:

  1. Power down the FP-1600 and remove it from the bank.
  2. Locate the slot on the bottom of the FP-1600 just above the label. Inside the slot, find the red reset switch.
  3. Looking at the FP-1600 so that the label is upright, use a pen or a small screwdriver to move the reset switch to the right.
  4. Power up the FP-1600 and wait for the red STATUS LED to flash. When the LED flashes, the FP-1600 is in reset mode.
  5. Power down the FP-1600 and move the reset switch back to the left.
  6. Re-attach the FP-1600 to the rail or the panel.
  7. Power up the FP-1600.
  8. Configure the FP-1600 in FieldPoint Explorer. Please see our FieldPoint Support page on  Troubleshooting FieldPoint Ethernet Configuration for a step-by-step guide to this procedure.

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