Using the 3402 DI to establish a "First Out" Monitor


#1

We have an eWON Flexy with 7 Digital Inputs configured as “limits”. When the system that is reporting the “limits” fails, all input states go to 0. I am trying to find a way to determine which limit was actually lost before the other 6 go to 0. I am afraid the cycle time is not fast enough to handle such as task. Has anyone used this configuration as a “First Out” Monitor successfully?


#3

Hello,

Could you please provide a backup with support files, so that I may review the tag structure and device settings? I would need this information to find a viable path for a solution to this issue.

Is this protocol ran through a script? Or, are you using the event logging to find the values?
Do you the frequency of the inputs changing? Example: The time period from which the inputs change from 0-6, then the time change for when the limit is reached.

Please let me know if I can provide any additional information.

-Kevin


#4

Hi Kevin,

Thanks for your response. I’ll give you a brief background on this project and will be able to send you the files for the tags, configuration, and program.bas when I get a chance.

We have a Fireye BunrerLogix Controller. It speaks modbus. It also has a limit string (7 relays NO). The relays are energized based on conditions that allow for safe operation of a natural gas fired burner. We’ve experienced an anomaly with several units reporting any “lockout” condition (Loss of a relay) in the limit string as the first relay in the string. We are trying to use the eWON and interposing relays to trap the actual relay that creates the lockout condition. Unfortunately, when a lockout occurs, all limits (relays) open. In simulation, we are catching the right modbus message from the BurnerLogix to the corresponding relay that is lost. When I send you the additional files, I will attach a manual for the Fireye unit so that you can have better understanding of this piece of equipment.

Thanks,

Micky Westmoreland


#5

#6

#7

I have attached the files that I would think you are looking for. Please let me know if you need anything else.

For HMS.zip (1000 KB)


#8

Hello,

Your best bet would be to create a script that activates on OnChange action. Creating a script that monitors the tags as they change, and once the limit is triggered, the script will record which tag toggled on the change. You can create a new tag to record the change, and have it save within the event logging.

I have attached our reference guide for the BASIC IDE that the Flexy uses.