Communication Errors Troubleshooting

When the Scanner is connected properly with a good quality RS-485 adapter or NuFlo USB adapter, communication errors should be rare. Depending upon your timeout settings, the layout of your wiring, or even the processing load on your Windows operating system, you may experience the occasional communication error; to resume operations, click Retry in the Communications Problem dialog box. However, if you are having consistent communication errors, there is a problem that needs to be addressed.

The following is a list of possible problems and solutions. If you cannot resolve the problem after trying these solutions, contact technical support. Please make a note of all troubleshooting steps attempted and of the results, and be prepared to discuss this information with technical support.


Incompatible Decimal Symbol
(Regional Settings)
Before attempting a connection with ModWorX Pro, make sure the decimal symbol in the Regional and Language Options settings on your computer is configured as a PERIOD. The use of a COMMA as a decimal symbol will prevent ModWorX Pro from connecting to an instrument. To change the decimal symbol, enter the Control Panel and select Regional and Language Options. Select the Regional Options tab and click Customize.
Express Connect Problems Express Connect allows the program to detect the Scanner regardless of the device's baud rate and slave address settings. If you are not able to connect to the instrument with Express Connect, try the Specify Parameters connection method to specify the slave address, baud rate and timeout. Express Connect is not recommended for connecting to multiple instruments.
Multiple Device Networks The Express Connect method is not recommended when connecting to multiple instruments. For multiple device networks, use the Discover Devices or Specify Parameters connection method. Each Scanner in the network must have a unique slave address.
Bad Connection Check that the connections between your computer and your RS-485 adapter or NuFlo USB adapter, and from your adapter to the Scanner, are secure. Also, confirm the polarity of the wiring from the converter to the instrument. For more information on wiring the converter, refer to the Quick-Start Guide or Hardware User Manual for your Scanner model.
NuFlo USB Driver Issues

If the Scanner is equipped with a NuFlo USB Adapter but the NuFlo USB Adapter does not appear as a COM port selection in ModWorX Pro, verify that the NuFlo USB driver has been installed per the instructions provided. If the driver is properly installed, see the NuFlo USB Adapter Troubleshooting Tips for help in identifying other possible causes of driver-related connection problems.


Power Problem Check that the Scanner is receiving adequate power, and that the power connections are secure.
Timeout Period Too Short The default timeout period may be too short to ensure a connection. To increase the Timeout Period, go to the Tools menu, select Options, select the Communications tab, and change the timeout value. A long timeout period does not directly affect the time required for the device to respond, only how long the program will wait for a response before giving up and reporting an error. If you specify a long timeout period, you will wait longer for the program to return control to you when communication errors do occur.
Line Noise Check that your RS-485 wiring is not routed near sources of electrical noise, such as electric motors. If minor line noise cannot be avoided, it may be helpful to lower the baud rate of the device. Increasing the number of retries in the Communications section of the Program Options dialog box may also help.
Not Enough Retries If the program does not receive a valid response from the device within a timeout period, the program will automatically resend the message a certain number of times before finally reporting a communications error. By default, the program will re-attempt each communication two times before it gives up. To increase the number of retries, go to the tools menu, select options, and increase the value in the Number of Retries field in the Communications section of the Program Options dialog box. Line noise can corrupt messages exchanged between the program and the device, and increasing the number of retries can improve the chances of a successful connection.
  Setting a high number of retries will not directly affect communications speed when there is a good connection, since there would be very few actual retries. However, setting a high number of retries will result in longer waits for the program to return and report an error when there are communications difficulties.
Specific Baud Rate Required If you are using a radio link, a virtual COM port, or an Ethernet serial converter, ensure that the baud rate set in the device is supported by the intermediate link.
Baud Rate Too High If you have a long wiring network, have many devices on your network, or have line noise, try a slower baud rate to achieve reliable communication to your devices.
Device Bus Delay Too Short Increase the time that the Scanner waits before responding to Modbus commands by increasing the Bus Delay value in the device. You do not need to adjust the program's timeout periods to account for the Bus Delay. This is done automatically by the software.
  In some cases of consistent timeouts, it may be helpful to slow the Scanner's message response rate by increasing the Bus Delay in the Configure Communications screen to at least 50 msec to prevent the response from being missed by the software.
Presend Delay Too Short Increase the time that the program waits between consecutive Modbus commands by increasing the Presend Delay value in the Communications section of the Program Options dialog box.
Device Parameters Changed While Connected If you manually change the communications parameters (slave address, baud rate) of the Scanner from the instrument keypad, the program will not detect the change. Return to the Welcome Screen and re-connect to the device.
RTS Control Not Properly Set Your RS-485 adapter may require that the RTS line of the COM port be toggled to control the direction of data flow for transmit and receive. If so, ensure that the "Toggle RTS line" option is enabled in the Communications section of the Program Options dialog box. Alternatively, if you are connected to a modem device on your COM port that requires that the RTS line be used in the standard way for RS-232 flow control, the "Toggle RTS line" option is disabled.
Spontaneous Loss Of Communication If for some unknown reason, the program stops communicating with the Scanner while you are using the program, return to the Welcome Screen and re-connect.
Device Needs To Be Reset If the settings in the Scanner become corrupted or are changed in such a way as to cause the device to fail to communicate with the software, reset the Scanner to factory default settings by pressing the three buttons on the faceplate of the device simultaneously and releasing. The device will load factory default settings and show "DEFALT" on the LCD briefly.
  CAUTION: Loading factory default values will lose all configuration values, such as the plate size, gas constituents, K-factors, etc. However, logged data will remain intact.
Restart Program An unexpected software error may have occurred that is interfering with communications. Close the program and run it again. If the problem persists, close all programs and restart your computer.
Windows Too Busy If you are running a large number of programs or a few CPU-intensive programs at the same time as ModWorX Pro, the processing load on Windows may cause delays in serial port processing. When this happens, the program is not receiving data from the COM port fast enough, even though the data was transmitted by the device in time, and timeouts will occur. Reduce the load on Windows by closing some of the other programs.
  Switching between programs also increases the operating system load by causing Windows to perform various system activities. If you switch away from ModWorX Pro while it is busy communicating with the device, it may cause a delay in Windows delivering data from the serial port to the program. Also, when ModWorX Pro is in the background, it receives a smaller percentage of the CPU's processing time, and will run more slowly. If the program is in the process of completing a communication-intensive operation, this reduction in processing power may cause communication problems. If you notice problems when you switch away from ModWorX Pro, close the other programs, or keep ModWorx Pro in the foreground while it is being used.
  Systems with faster CPU's and more memory will be less likely to experience these types of problems.

Contacting Technical Support

Phone: +1 844 226 6327
Email: ms-services@cameron.slb.com
Web: http://www.cameron.slb.com/flowcomputers