KB89407
Published: November 20, 2020
Revision: 1.0

PID Output Remains Invalid (QNAN)


Applies To:

Firmware for:

  • GRV-EPIC-PR1
  • GRV-R7-MM1001-10

Versions Affected:

GRV-EPIC-PR1: 1.5.0 to current
GRV-R7-MM1001-10: All versions


Symptoms:

In either of the following situations, if the PID Input goes to "Invalid Value" (QNAN), the PID Output will also go to and remain stuck at "Invalid Value" (QNAN) even if the PID Input returns to normal, which is incorrect behavior:

  • During I/O configuration while the PID is scanning,
  • During normal PID operation.

Workaround:

To clear up the "Invalid Value" for the PID Output, do one of the following:

  • For PID algorithms Velocity Type C and Velocity Type B, set the PID output to any value either from the PAC Control Debug PID window or using PAC Control command Set PID Output.
  • For PID algorithms ISA, Parallel, Interacting, and the obsolete version of each, write zero to the PID Integral term in the memory map at offset 0x10 from each PID Status Area, at base address 0xF2000000. For example:
    • For PID 0: write to address 0xF2000010
    • For PID 1 write to address 0xF2000060
    • For PID 2 write to address 0xF20000B0
    • For PID 3 write to address 0xF2000100
    Note that each PID Status Area is 0x50 bytes in length.
You only have to do this once after the first time the PID Output goes to "Invalid Value" (QNAN).

Resolution:

Opto 22 has resolved this issue and will include the fix in an upcoming release.

Questions?

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


DISCLAIMER

This Opto 22 Knowledge Base ('OptoKB') article is intended to provide general technical information on a particular subject or subjects and is not an exhaustive treatment of such subjects. Accordingly, the information in this OptoKB article is not intended to constitute application, design, software, or other professional engineering advice or services. Opto 22 may modify the OptoKB articles at any time. Before making any decision or taking any action which might affect your equipment, you should consult a qualified professional.

OPTO 22 DOES NOT WARRANT THE COMPLETENESS, TIMELINESS, OR ACCURACY OF THE DATA CONTAINED IN THIS OPTOKB ARTICLE AND MAY MAKE CHANGES THERETO AT ANY TIME AT ITS SOLE DISCRETION WITHOUT NOTICE. FURTHER, ALL INFORMATION CONVEYED HEREBY IS PROVIDED TO USERS 'AS IS.' IN NO EVENT SHALL OPTO 22 BE LIABLE FOR ANY DAMAGES OF ANY KIND INCLUDING DIRECT, INDIRECT INCIDENTAL, CONSEQUENTIAL, LOSS PROFIT, OR DAMAGE, EVEN IF OPTO 22 HAS BEEN ADVISED ON THE POSSIBILITY OF SUCH DAMAGES.

OPTO 22 DISCLAIMS ALL WARRANTIES WHETHER EXPRESSED OR IMPLIED WITH RESPECT TO THE INFORMATION (INCLUDING HARDWARE, SOFTWARE, AND/OR FIRMWARE) PROVIDED HEREBY, INCLUDING THE IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, MERCHANTIBILITY, AND NON-INFRINGEMENT. Note that certain jurisdictions do not sanction the exclusion of implied warranties: thus, this disclaimer may not apply to you.

Copyright © 2020 Opto 22. All rights reserved.