There are modbus libraries in at least "C" to read devices... I read
the modbus info from our morningstar controllers...
On 10/26/23 1:08 PM, Forrest Christian (List Account) wrote:
Yes, and no.
The modbus protocol defines how to move data between two devices.
However, the contents of the data being passed is vendor-defined and
there aren't any industry standards I'm aware of (although it wouldn't
surprise me if there were).
Every vendor that produces a modbus-capable device usually publishes
some sort of guide to the modbus registers for each device. For
instance, a quick google search turned up this document:
https://www.vertiv.com/4ac5f2/globalassets/products/monitoring-control-and-management/monitoring/modbus-protocol-for-bdsu-reference-guide.pdf
"modbus register map" or "modbus communication guide" or simply
"modbus" when added to your vendor or product name often will turn up
the right document.
Just FYI, A couple of years ago, I would have suggested you provide me
with the vendor of the equipment, and I'd make you a firmware load for
the sitemonitor serial module to be able to read this, but that
codebase needs to be re-written to support the base 3. At some point
in the future I'm going to resume doing those requests in which case
you'd end up with a module which pulls data from this device.
Doesn't help you right now though.
On Thu, Oct 26, 2023 at 10:25 AM <[email protected]> wrote:
Is it likely that AC meters for monitoring circuits or subpanels
have a standard message format?
-----Original Message-----
From: AF <[email protected]> On Behalf Of Mark Radabaugh
Sent: Thursday, October 26, 2023 10:52 AM
To: AnimalFarm Microwave Users Group <[email protected]>
Subject: Re: [AFMUG] Modbus
Modbus is an ancient serial protocol to pass values back and
forth. It’s very open but also somewhat vendor specific. You
can send any message you like from A <->B but the two devices have
to know what the specific message means. Various industries have
defined the message content but I would be somewhat surprised if a
Vertiv rectifier knows what to do with the information from a meter.
Tons of information online, and it’s not a hard protocol to code
for. Used to do it in BASIC years ago. There are two
protocols - MODBUS and MODBUS RTU. The RTU protocol is much more
difficult to work with due to timing requirements, MODBUS itself
is just standard serial at a baud rate and timing of responses is
not critical at all.
Mark
> On Oct 26, 2023, at 7:38 AM, Adam Moffett <[email protected]>
wrote:
>
> I've never used modbus. I'm looking at AC usage meters that
support modbus over RS-485. And the controller on my Vertiv
rectifier says this in the manual:
>
> "e) Modbus Protocol: The NCU can communicate with an AC Meter
using the Modbus protocol."
>
> ....and that's literally all it says. Is this something
standardized where I can expect any modbus capable AC meter to
work the same? Is this plug and play or would I have to learn yet
another discipline?
>
> If it's not an easy answer I can take it to Vertiv tech
support. Just wondering if this group magically has the answer.
>
> --
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