Modbus/TCP unsupported function codes return erroneous packets

Applies To:

SNAP-PAC-EB1
SNAP-PAC-EB1-FM
SNAP-PAC-EB1-W
SNAP-PAC-EB2
SNAP-PAC-EB2-FM
SNAP-PAC-EB2-W
G4D32EB2
G4D32EB2-UPG
OPTOEMU-SNR-3V
OPTOEMU-SNR-DR1
OPTOEMU-SNR-DR2
SNAP-PAC-R1
SNAP-PAC-R1-FM
SNAP-PAC-R1-W
SNAP-PAC-R2
SNAP-PAC-R2-FM
SNAP-PAC-R2-W
SNAP-PAC-S1
SNAP-PAC-S1-FM
SNAP-PAC-S1-W
SNAP-PAC-S2
SNAP-PAC-S2-W

Versions Affected:

Problem affects firmware versions: R9.3c and lower
Problem is fixed in firmware version: R9.3e

Resolved In Version:

Problem is fixed in firmware version: R9.3e

Symptoms:

When an unsupported Modbus/TCP function code is sent to a SNAP PAC brain or controller, it responds with an invalid response rather than the expected Modbus/TCP Invalid Function Error. If the invalid command is the first to be sent to the brain or controller, it will respond with zeros. If another command has been sent before the invalid command, the response will reflect the last valid command.

Workaround:

The only workaround is not to send an unsupported Modbus/TCP command.

Resolution:

Opto 22 has resolved this issue.

Questions?

Contact: Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
Email: support@opto22.com

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