So basically, you're logged in on the meter, but the access level is insufficient to read that value.

Perhaps the password is wrong? Or you can sometimes leave it out to do a Public login.

It is possible that the login you've done on the meter is supposed to be encrypted, but since you logged in unencrypted, even though the login was successful, you don't have any access to actual values on the meter.

Are you sure it is not an Hexing HXE130? Sometimes on these meters, the modem has already logged in on the meter, and when you do a Nested login, the second login doesn't have any access. So on these meters, there is a checkbox you can tick on Advanced Meter Setting, to not do the Cosem login on connect, but assume it is already logged in. That usually would sort out that problem, however you have to back off maybe 10 minutes perhaps more, to give the logged in sessions a chance to time out, after you did the setting, to give it a chance to work.

..or perhaps the previous person logged in, and the session didn?t time out yet, and then the person reconnected and did a nested login?. in that case, back off for 10 minutes to give the meter session a chance to time out.

So in the case of nested logins, or a login on a meter that needs encryption, or sometimes using a public login, the session you end up with does not have sufficient access to read values. This can also happen when a DC cannot access a meter.

The D8h value is indicative of ?not found?, in a more profound way than a normal GET error. Not only doesn?t he allow you to read a certain value, it doesn?t even find the value to read. Like on some Data Concentrators, it would give you D8 when it cannot contact the meter.

So with some GET errors, at least it gives you a C4 with an error code in the reply. But when it gives you a D8, the error is much more profound.