Feature request: Optionally ignore modbus packet size restrictions, use TCP packet length
Bug #341708 reported by
n1ywb
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| libmodbus |
Invalid
|
Medium
|
Unassigned | ||
Bug Description
For our in-house Modbus TCP implementations we ignore the silly 260 byte / 125 register limitation on modbus packet sizes. The "quantity of registers" field is two bytes and so can theoretically support up top 2^16 registers, and we allow that. For response packets we ignore the modbus packet length field and instead look at the TCP segment length to determine packet size.
| Changed in libmodbus: | |
| status: | New → Invalid |
Revision history for this message
| Stéphane Raimbault (sra) wrote | #1 |
| Changed in libmodbus: | |
| importance: | Undecided → Medium |
| milestone: | none → 2.0.3 |
| status: | Invalid → New |
| Changed in libmodbus: | |
| milestone: | 2.0.3 → 2.2.0 |
| Changed in libmodbus: | |
| status: | New → Invalid |
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We can add a new method modbus_something (to not break the API) to remove this limit in mb_param. It's important to be conform to the standard and I'm agree to be able to workaround when it's silly!
With a unit test... :)