SiteOnline is a web based software package to display information, OPC2SQL is one of many options SiteOnline has for communicating to remote devices. Errors returned by OPC2SQL are depend on where in the polling process the error occurred. The following is a list of steps to communicate with a remote device and successfully poll the values requested.

1. The server assembles the points and registers and sets the requested format for each, which must match the remote meter
2. Establish communications to the remote communications device, example: modem, satellite terminal, remote IP terminal server
3. Request and establish a connection to the remote meter. This means the Device ID for a TotalFlow, or Modbus address for a modbus meter, is broadcast over the communications link and that meter has to respond within a specified amount of time.
4. Groups of registers are sent to the remote meter, the system then waits a limited amount of time for the meter to return the values
5. Values returned are then converted to the registers using the formats originally defined
6. Data is stored in the database for the website

The following is a list of errors that can show on the website, they error shown is dependent on the meter type and the communications:

• Error Reading Item...Quality Bad/Quality Uncertain
  • Communication was most likely established, but Step 5 above most likely failed.
• Comm Error: Attempt to Connect to Communications Channel Failed.
  • Step 2 above failed, no basic communications connection was able to be established
• Comm Error: Attempt to Connect to Device Failed.
  • Step 3 above failed, basic communications was established, but not communication to device was made
• Comm Error: Circuit Connection Disconnected.
  • The main communications link was broken, generally after being established.
• Comm Error: Requested Object or Function has NOT been initialized properly.
  • This would be a communications issue within the polling engine.
• Comm Error: The operation completed successfully.
  • This is a very misleading error, the communication link was not able to be established.
• Comm Error: The Read Request Has Timed Out.
  • Communications to the device was successful, however step 4 above failed because the device did not return within the specified amount of time.
• Comm Error: The value of the handle is invalid
  • This is caused when the meter returns unexpected information.
• Error talking to meter
  • Communications was established but step 2 above when trying to talk to the device failed. Generally either the device never answered or the answer was not
• Item Error...Quality_Bad+Not_Connected
  • Communication channel was opened, but communication to end device failed. Step 3 above.
• Item Error...Quality_Bad+Comm_Failure
  • Communication channel in step 2 above failed, either started and then lost communication or was never able to establish communications.
• Item Error...Quality_Bad+Bad
  • Step 5 above had values from the meter that did not fit into the correct format for the registers or the quality of the data could not be trusted.
• Polling Engine was unable to respond to the request within 30 minutes
  • A demand poll was requested but was not able to be responded to by the polling engine within 30 minutes.
• Read did not complete in (n) seconds
  • The polling engine gives the meter a certain amount of time to respond, in addition OPC2SQL gives the polling engine so long to respond. This error occurs when the polling engine did not respond to OPC2SQL within a given amount of time, check the time out and retry settings within the polling engine.
• Read never completed
  • The polling engine gives the meter a certain amount of time to respond, in addition OPC2SQL gives the polling engine so long to respond. This error occurs when the polling engine did not respond to OPC2SQL within a given amount of time, check the time out and retry settings within the polling engine.
• The remote procedure call failed.
  • This is an error within the polling engine.
• The RPC connection is disconnected.
  • This is an error within the polling engine.
• Timed out waiting for OPC2SQL
  • The OPC2SQL server did not respond to the request within a specified amount of time.
• Unable to talk to meter
  • Step 2 or step 3 above, a generic error usually refers to a communications failure or communications never being able to be established.
• Unspecified error
  • Unknown error returned from polling engine.
• Poll Error
  • TMS communication was established, but data did not follow the correct format
• Poll No Answer
  • TMS modem did not answer
• Poll: Incorrect Function
  • Protocol error with remote device, generally requesting a modbus address with an incorrect function code. The error is generated from the remote device.