KB55299
Published: March 20, 2007
Revision: 2.0

Divide by zero operation returns valid results in ioControl strategy


Applies To:

SNAP-UP1-ADS
SNAP-UP1-M64
SNAP-UP1-D64
SNAP-LCE

Versions Affected:

Problem was discovered in version: R7.1
Problem is fixed in version: R8.0a PAC Control

Resolved In Version:

Problem is fixed in version: R8.0a PAC Control


Symptoms:

Dividing by zero in an ioControl strategy returns a valid result from a control engine. Dividing a positive integer by zero returns 0x7FFFFFFF, and dividing zero by a negative integer returns 0x80000000.

If a float value is divided by zero, 1.#QNAN (‘not a number’) should be returned, but is not.

Consequently, OptoOPCServer may stop scanning, causing ioDisplay to not update values, even though the ioDisplay computer continues to communicate to the controller.


Resolution:

Opto 22 has resolved this issue. If a float value is divided by zero, an error is added to the queue, and 1.#QNAN is returned. The integer behavior remains the same.


Questions?

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


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