Our 1756-L55 system is equipped with 2 Devicenet scanners, one with over 50 nodes and the other with less than 10 nodes. While the system operates fine 90% of the time, nodes occasionally drop off due to power outages or other issues. To address this recurring problem, we are considering adding a 'node status' indicator to the HMI for future debugging purposes. However, we are unsure how to extract this information from the scanner, which features a 124-element DINT array for Input/Output status monitoring/control. The network comprises mainly 1791D-16BO modules and some valve banks. We are seeking the most efficient method to obtain the status of each node for display. Though each module has 2 allocated elements, it is uncertain whether these elements contain any status information. While one option is to incorporate an 'always on' input for each node, the availability of such features on each node is unclear. Retrieving the status data appears to be the optimal solution.
Setting up the 1756-DNB is simpler than you might think. In addition to the standard Input and Output Connections, this device features a Status connection containing 32 double-words. This connection provides essential status information, such as the DeviceFailureRegister, a SINT[8] array indicating node addresses on DeviceNet. When a connection fails, the corresponding bit is triggered. The DeviceStatus array, a SINT[64] array, displays error codes for any broken connections. A common occurrence is seeing fault code 72 for a powered-down device or code 77 for a size mismatch. The 4-byte StatusDisplay array translates what's on the dot matrix display on the front of the 1756-DNB into ASCII format, making it easy to integrate with an HMI. Don't forget to check out the Diagnostic Faceplate for FactoryTalk View SE/ME, available on the Samplecode website, which seamlessly connects to the Status connection of the 1756-DNB.
Ken, your information is invaluable. I failed to notice the Sregister before, but if I had taken a closer look, I would have found it! Ken Roach mentioned the DeviceStatus array, a SINT[64] array that provides error codes for broken connections. The most common codes are 72 for a powered-down device and 77 for a size mismatch. Where can I locate the detailed error code explanations? I'm considering adding a table to the SCADA system with status indications and fault codes to further assist the maintenance team.
Ken Roach mentioned the availability of a Diagnostic Faceplate for FactoryTalk View SE/ME on the Samplecode website, designed to seamlessly connect to the Status connection of the 1756-DNB module. If you are wondering where to locate this valuable diagnostic tool, look no further than the Samplecode website.
It sounds like you're dealing with a complex setup, but adding a 'node status' indicator to the HMI is a great idea for troubleshooting. To extract the status information from your DeviceNet scanners, check the DeviceNet Object (specifically the 0x1E status object) for each node; it usually provides useful diagnostic data. You might also want to utilize the status word from each module, which can indicate the operational status and any errors. If your nodes support it, consider leveraging the “NODE” status service to query the status directly. Additionally, for those modules that might not have inherent status bits, touching base with the documentation or the vendor could clarify if those bits are available or if there’s a standard method for monitoring them. Good luck!
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Answer: Answer: One efficient method to obtain the status of each node for display is by extracting information from the scanner's 124-element DINT array for Input/Output status monitoring/control. Incorporating a 'node status' indicator on the HMI can aid in future debugging purposes.
Answer: Answer: To efficiently retrieve status data, consider leveraging the allocated elements in each module, if available, or explore the possibility of incorporating an 'always on' input for each node. This can help in monitoring the status of nodes within the system.
Answer: Answer: By implementing a method to extract status information from the DINT array in the scanners and utilizing features like 'always on' inputs, you can achieve consistent monitoring of nodes across the system. This proactive approach can help in addressing node drop-offs caused by power outages or other issues.
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