Test Without CCA

[Bobsilvio]

I was trying to see the data flow without CCA, so powering at 24v and capturing the data from A and B with a rs485.
But I do not receive a useful data, have you ever tried?

`RS-485 Sniffer

00 FF 00 00 00 00 FF 00 FF 00 FF 00 FF 00 00 00 FC 01 00 FD 00 00 FF 00 00 00 00 00 00 00 FF 00 FF 00 00 FE
00 00 00 00 FC 00 FF 00 00 00 00 FE
00 00 00 00 FF 01 FF 00 FF 00 00 FF 00 00 FF 00 00 FF 00 00 FF 00 00 00 FD 00 00 FE
00 01 FF 00 00 FF 00 00 00 00 00 00 01 FC 00 00 00 FE
00 00 00 00 00 00 FE
00 00 00 00 00 FC 00 00 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 FF 00 FF 00 FE
00 00 FF 00 00 00 FD 00 FF 00 FC 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 00 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 00 00 FF 00 00 00 FE
00 FE
01 00 00 00 FF 00 00 00 FE
00 00 00 FF 00 FF 00 FF 00 00 00 00 00 01 00 00 00 FF 00 FF 00 00 FE
00 00 00 00 00 00 FF 00 00 FF 00 00 00 00 00 00 00 FE
00 00 FF 00 FF 00 00 FF 00 00 00 00 00 00 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 FE
00 00 00 FF 00 FF 00 00 00 FE
00 00 00 00 00 00 00 00 FF 00 FF 00 00 00 00 00 00 00 00 00 FD 00 FE
00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 FF 00 FF 00 FF 00 00 00 00 00 FC 00 00 00 FE
00 FF 00 FF 00 00 00 FF 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 FF 00 FF 00 00 FF 01 00 FF 00 FF 00 00 00 FF 00 FF 00 00 00 00 00 00 00 FF 00 00 FF 00 00 00 00 00 00 FE
00 FF 00 FC 01 FF 00 00 00 00 00 00 00 FC 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 00 00 00 00 FF 00 00 F8 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 FF 00 FF 00 00 FE
00 00 00 00 00 00 00 00 00 00 00 FE
01 FF 00 00 FF 00 FF 00 FF 00 FE
00 00 FF 00 00 00 00 00 00 00 00 FE
00 00 FF 00 00 00 FF 00 00 00 00 00 00 00 00 00 FC 00 FC 00 00 FC 00 FF 00 FF 00 FD 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 00 FF 00 00 FE
00 00 00 00 00 FF 00 00 00 FF 00 FF 00 00 FF 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 00 00 00 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 FF 00 00 00 00 00 FF 00 00 00 FF 00 FF 00 FF 00 00 00 00 00 00 01 00 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 FE
00 00 FC 00 00 FC 01 00 FF 01 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 FE
00 FF 00 FF 00 00 FF 00 00 00 00 00 00 00 FE
00 00 FF 00 00 FF 00 FF 00 FF 00 00 00 00 00 00 FE
00 00 FF 00 00 01 00 00 FF 00 00 FF 00 FE
00 FF 00 FF 00 FF 00 FF 00 FF 00 00 00 FF 00 00 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 FD 00 FF 00 00 00 00 FE
00 FF 00 FF 00 00 FF 00 FF 00 00 00 00 00 00 00 FE
00 FA 00 00 FF 00 00 00 00 00 00 00 00 FF 00 FF 00 00 FF 00 FF 00 FF 00 00 00 00 FC 00 FE
00 FF 00 00 00 00 00 00 FF 00 FF 00 00 00 00 00 00 00 00 FD 00 00 FE
00 FF 00 00 FF 00 FF 00 00 00 00 00 FE
00 00 FD 00 00 FC 00 00 00 00 00 00 00 FF 00 00 FF 00 FF 00 FF 00 FF 00 00 FF 00 00 00 00 00 00 FE
00 00 00 00 00 00 00 00 00 FF 00 FE
00 FF 00 FF 00 FF 00 00 FF 00 00 00 FF 00 00 FE
01 00 00 00 00 FC 00 00 00 00 FF 00 FF 00 00 00 FE
00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 FF 00 01 00 01 00 00 00 00 00 00 FF 00 01 FF 00 00 FF 00 00 00 00 00 00 00 00 FC 00 00 00 FF 00 00 FF 00 00 00 FE
00 FF 00 FF 00 FF 00 00 00 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 FC 00 FF 00 00 FF 00 00 FF 00 FF 00 FF 00 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FE
00 FF 00 00 00 FF 00 FF 00 FE
00 FF 00 FF 00 FE
00 00 FF 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 00 00 FF 00 FE
00 FF 00 FF 00 FF 00 FF 00 FF 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 FF 00 FF 00 FE
00 00 01 00 00 FF 00 FF 00 FF 00 FF 00 00 FE
00 00 00 00 00 FF 00 00 FF 00 FF 00 FF 00 00 FF 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 FE
00 00 00 00 00 00 00 00 00 00 FF 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 FD 00 FF 00 00 FE
00 FF 00 00 00 00 FC 00 FF 00 00 FC 00 00 00 00 00 00 00 FE
00 FF 00 FF 00 00 FF 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 FF 00 FF 00 FC 00 FF 01 FF 00 FF 00 00 00 00 00 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 FE
00 00 00 00 00 01 00 00 00 00 00 00 00 01 FF 00 00 00 00 00 00 01 00 FF 00 00 00 00 00 00 00 00 00 00 FF 00 00 00 00 00 00 FD 00 01 00 00 00 00 00 00 00 FF 00 00 FD 00 00 00 00 00 00 00 00 00 00 00 FC 00 00 00 00 00 00 00 00 00 00 00 FC 00 00 FF 00 FF 00 FC 01 FF 00 FE
00 00 00 00 00 FE
00 FE
00 00 00 00 00 00 00 00 00 00 FF 00 00 00 FF 00 FF 00 FF 00 FF 00 FF 00 FF 00 00 FF 00 00 FE
`

[willglynn]

CCAs (or MMUs, or similar) are required to:

1. Configure the system when installed
2. Operate the system, and
3. Ask the system for data

Configuration is difficult to reverse engineer – my system is already set up, and I don't want to tear it down just to see what configuring it would require. It's also failure-prone, since even if I saw which messages were sent to configure my system, I would be guessing about why those messages were sent.

Operation includes safety-relevant tasks like implementing PV rapid shutdown, as well as other potentially important tasks, like sending directions to optimizers. Replacing former usually requires regulatory approval, and the replacing latter requires additional work from someone else, since my system operates its optimizers in distributed mode.

In terms of asking the system for data: gateways do not transmit messages unless asked, so CCAs spend most of their time sending receive requests to see if they have anything to say. As the README alludes, it would be possible for taptap to ask the system for data. Would this be useful to you, even without the two other functions?

[Bobsilvio]

I just disconnected the jack and powered it at 24v (if you see where there is + and - there are 24v), so no special operation is needed.
And as usual connect A and B with rs485, but I saw that without CCA it does not give me information, so in my opinion it must send or request something to the tap.

[willglynn]

Yes, I already explained why. Is your system already configured, and do you expect not to ever replace modules? Does your jurisdiction require rapid shutdown certifications? What is your application where just getting data is useful?

[Bobsilvio]

Actually my CCA is broken and I'm waiting for its replacement, and I tried to read the data from the panels.

[willglynn]

Gotcha. I know how to make taptap actively interrogate gateways without a CCA/MMU, but I've not been convinced it makes sense to build as a feature, given that a CCA/MMU is still required for other functions. It sounds like your use case is a temporary one, which is valid, but is not an indication that this feature would be broadly applicable.

[bublath]

Do you have a prototype that would send a receive request? All I'm interested in is monitoring the current state of all panels in range. Or would that also require configuration first for a system that never got configured in any way?

[mekket]

Gotcha. I know how to make taptap actively interrogate gateways without a CCA/MMU, but I've not been convinced it makes sense to build as a feature, given that a CCA/MMU is still required for other functions. It sounds like your use case is a temporary one, which is valid, but is not an indication that this feature would be broadly applicable.

@willglynn Did I understand correctly that there is a way to get the panel level data from optimizers without a CCA? In my country the rapid shutdown is not required and many users(me included) have the optimizers just for shaded panels or different orientation installs. It would be great to get the data without the added cost of CCA. TAP itself is not that expensive. I would be interested in trying to figure out the process myself if you are willing to share ideas.

[MartB]

Same would be great to get the interrogation going, the CCA only does 10mbps which is incompatible with my switch. I only use it for monitoring

[RAR]

@willglynn did you ever try to send a command to the gateway? I'm trying to inject a command with the CCA attached and the gateway seems to just ignore it completely. Even if i pick the next Seq number ahead of the CCA and throw it in between CCA requests.

There isn't any auth in those frames so its not like the gateway would know its coming from something other than the CCA.

I'm mainly interested in requesting it to send Frame 0x27 data by sending a 0x26 frame.

Very odd.