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 3.0.0
GRV-R7-MM1001-10: All versions prior to 3.0.0

Resolved In Version:

GRV-EPIC-PR1: 3.0.1
GRV-R7-MM1001-10: 3.0.0

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

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