Cognex In-Sight Micro - Monitoring Current Job in the PLC?

I'm looking for a better way to manage job changes in several machines I've done with Cognex In-Sight Micro cameras. These are In-Sight Micro 1403s communicating with a 1769-L32E (v 17) over Ethernet/IP.

The way I'm doing it now is whenever I change jobs I save off the previous criteria into a buffer and whenever I acquire a new barcode, I compare it to the previous code and if the right things are different, I change jobs.

The issue I have is what happens when some external force (in this case, an electrical issue) "resets" the camera jobs without the PLC knowing it?

What I would like to do is continuously monitor the current job in the cameras and then if I see a mismatch, change jobs. However, this does not appear to be a part of the standard IO assembly in the Logix program. So if this is possible it looks like I'll have to Explicit Message. I've been trying to find manuals online for this but the cognex site keeps giving me "service unavailable" errors. So my question is twofold.

1) Is it possible to use Explicit Messaging to read a string from the Camera so I know what the current job is?

if so,

2) Does anybody have access to a PDF manual I can look at?

Thanks.

I had this problem before. That time I simply put an constant integer value into the 'job' and output it over Ethernet IP as an interger value to the PLC. This value is constantly updated if the camera is online so the PLC can see which job is actually live on the camera.

I also use the EIP to monitor if the camera is online and display a message if it's not. This is in case the power cycling or whatever cause the camera to not go back online (or if someone just forget to put the camera back online).

You're in luck, it is possible to use an explicit message to read a string to tell you what the current camera job is. This is how I'll typically do job changes in Cognex Insight Micro cameras. I have done this recently.

Message configuration:

Message type: CIP Generic
Service Type: Get Attribute Single
Service code: e (hex)
Instance: 1
Class: 78 (hex)
Attribute: 14 (hex)

Destination element is a SINT array. Copied that to a string with a length to get the job name, knowing that the job names I use are a fixed length.

I would cycle this message once per second without issue.

The solution that kku proposed is also a good one. I like that. Elegant and simple to use an integer within the job file to identify the job.

MerryChrisSmith said:

You're in luck, it is possible to use an explicit message to read a string to tell you what the current camera job is. This is how I'll typically do job changes in Cognex Insight Micro cameras. I have done this recently.

Message configuration:

Message type: CIP Generic
Service Type: Get Attribute Single
Service code: e (hex)
Instance: 1
Class: 78 (hex)
Attribute: 14 (hex)

Destination element is a SINT array. Copied that to a string with a length to get the job name, knowing that the job names I use are a fixed length.

I would cycle this message once per second without issue.

The solution that kku proposed is also a good one. I like that. Elegant and simple to use an integer within the job file to identify the job.

Click to expand...

I'm writing to this same attribute to do job changes, so it makes sense. The first SINT is the length I believe elements 2-32 are the actual character values. So those can be read back? It isn't an attribute that is cleared out after the job is changed or anything like that? (I realize that isn't likely, I'm just trying to anticipate curveballs)

After looking back at my program, yes, the SINT[0] is the string length. The characters of the job name start at SINT[2].

So those can be read back? It isn't an attribute that is cleared out after the job is changed or anything like that

Click to expand...

I don't believe so. This method worked pretty well to verify job changes in my Insight Micro.