Coming from an embedded C world, I have the problem that I want to protect my machine parameters from unwanted changes, log changes, and notify others about changes etc.
I gather that normally the PLC has no security for it's tags, and is left wide open. Leaving the HMI / Scada layer to deal with access permissions, change control / logging etc.
Are there any stardard patterns, or systems that PLC guys use to do this on the PLC? I've got around 1000 parameters that need to be looked after.
The only thing I can think of is to have the parameters stored in an AOI as a linear array of a standard type to protect them, with a mirrored copy in controller tags. The pain is that it's not exactly efficient, and array access isn't that great for efficeiency, reliabilty, safety, and most of all maintainability. Ideally I'd give each paramter a unique id (eg a tag name, or code number), and use binary search / dictionary look ups, but that's not possible here.
If a controller tag is changed remotely, eg via remote tag write say from another PLC, HMI, or embedded device, can an event be triggered from it to do range checking, validation etc, permission check?
Running on CompactLogix L43 V17 for what it's worth.
I gather that normally the PLC has no security for it's tags, and is left wide open. Leaving the HMI / Scada layer to deal with access permissions, change control / logging etc.
Are there any stardard patterns, or systems that PLC guys use to do this on the PLC? I've got around 1000 parameters that need to be looked after.
The only thing I can think of is to have the parameters stored in an AOI as a linear array of a standard type to protect them, with a mirrored copy in controller tags. The pain is that it's not exactly efficient, and array access isn't that great for efficeiency, reliabilty, safety, and most of all maintainability. Ideally I'd give each paramter a unique id (eg a tag name, or code number), and use binary search / dictionary look ups, but that's not possible here.
If a controller tag is changed remotely, eg via remote tag write say from another PLC, HMI, or embedded device, can an event be triggered from it to do range checking, validation etc, permission check?
Running on CompactLogix L43 V17 for what it's worth.
