Controllers accessing Ethernet brains via high-latency radio network may reset

Applies To:

SNAP-PAC-S1
SNAP-PAC-S2
SNAP-PAC-R1
SNAP-PAC-R2

Versions Affected:

Problem was introduced in version: R1.0a
Resolution is included beginning in version: B8.5a, build date August 14, 2009, 9:12 am
Problem is fixed in version: R8.5a

Resolved In Version:

Problem is fixed in version: R8.5a

Symptoms:

A SNAP-PAC control engine communicating to an Ethernet brain over a radio modem (or a wireless device with a high latency response time such as a cellular modem), may reset because of the delay in receiving a response from the brain. If the control engine sends a command and does not receive a response from the brain within the configured timeout period set up in the strategy, then the control engine retransmits the message. When responses to the original and retransmitted request are received by the controller, the conditions are set up for the reset to occur.

An example of a SNAP-PAC Ethernet system with radio modems:

A SNAP PAC control engine is connected via Ethernet to a radio modem. At a remote location, a radio modem is connected over Ethernet to a SNAP PAC Ethernet brain.

Workaround:

Increase the timeout period for a response from the brain to the controller. From PAC Control configure mode, select Configure→I/O, highlight the I/O unit, and click Modify to display the Edit I/O Unit dialog. Change the Timeout value and click OK to complete the change. Click OK again to close the remaining windows. The image below shows the timeout setting for an I/O unit.

Resolution:

This problem has been fixed.

Questions?

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

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