Opto 22 - Resources & Tools

Cannot add modules to a SNAP I/O unit after changing the type from “Generic OptoMMP Device” in PAC Control

Knowledge Base - KB91442 - 7/31/2026

In PAC Control Configure mode, you may not be able to add modules to an I/O unit after changing its type from Generic OptpMMP Device to a SNAP I/O unit.

Not all SNAP-IDC5Q points appear in the PAC Control Inspect I/O Unit dialog

Knowledge Base - KB91438 - 7/31/2026

When inspecting an I/O unit in PAC Control Debug mode, only the first point of a SNAP-IDC5Q module may appear on the Points [Detailed] and Points [Compact] tabs of the Inspect I/O Unit dialog (double...more

Find & Replace Tag in subroutine replaces substring globally rather than locally

Knowledge Base - KB91408 - 7/31/2026

If you are in a subroutine and choose Edit > Replace and then choose Tag in the Search For field in PAC Control, the replacement may not occur locally within the subroutine, as expected. Instead, the...more

64-bit integer values in OptoScript blocks may be misinterpreted in a PAC Control strategy

Knowledge Base - KB91402 - 7/31/2026

When using the 64-bit integer value of -9223372036854775808i64 in an OptoScript block, it is treated as -9223372036854775807.

Importing a chart containing legacy I/O into a strategy not enabled with Legacy options may hang PAC Control

Knowledge Base - KB91399 - 7/31/2026

When attempting to import a chart that contains legacy I/O units into a strategy that is not enabled with Legacy options, PAC Control may hang.

Find and Replace > Table Index may crash PAC Display

Knowledge Base - KB91378 - 7/31/2026

If you encounter a Precondition error message when running a Table Index search in the Find and Replace dialog in PAC Display Configurator, PAC Display may crash if you select Abort or Retry instead of Ignore.

PAC Display may crash when opening or saving a project with a corrupt window file

Knowledge Base - KB91387 - 7/31/2026

When opening or saving a project with a corrupt window file, PAC Display may crash without any error messages.

Combo box with graphic dynamic attributes may not function in PAC Display Runtime

Knowledge Base - KB91390 - 7/31/2026

In PAC Display Runtime, when closing and reopening a window that has a combo box with graphic dynamic attributes, the combo box may not function.

Using AutoCorrect Tags with large project files may crash PAC Display

Knowledge Base - KB91381 - 7/31/2026

When using the AutoCorrect Tags tool for large project files, PAC Display Configurator may crash.

Entering Debug mode after block changes in Online mode may crash PAC Control on Windows 11

Knowledge Base - KB91316 - 7/30/2026

In PAC Control on a Windows 11 computer, when you attempt to enter Debug mode after making a strategy change to an Action or OptoScript block in Online mode, PAC Control may crash with the online change failing to download.

Controller or control engine may unexpectedly reset if strategy has subroutines

Knowledge Base - KB91315 - 7/30/2026

A controller or control engine may unexpectedly reset if the PAC Control strategy contains subroutines.

OptoScript blocks in PAC Control may be missing the Pointer Variable type in the Select Variable dialog for subroutines

Knowledge Base - KB91314 - 7/30/2026

When attempting to create a local pointer variable in a subroutine using an OptoScript block in PAC Control, the Pointer Variable option may be missing from the Type list in the Select Variable dialog box.

PAC Control “Features” field inaccurate for mixed I/O modules and groov RIO modules configured with On/Off-Time Totalizer features

Knowledge Base - KB90974 - 7/30/2026

The Features field for digital inputs in the Edit Digital Point dialog in PAC Control Configure mode may incorrectly show None for mixed I/O modules (GRV-MM1001-10) and groov RIO modules (GRV-R7-MM1001...more

Results from the Find feature in PAC Control may not accurately list all I/O point reference counts

Knowledge Base - KB81864 - 7/30/2026

When using the Find feature (Edit > Find) in PAC Control Configure mode, the results may not accurately list all I/O point references and cross-references.

I/O point references in PID loops are not included in Find results in PAC Control

Knowledge Base - KB80680 - 7/30/2026

When using the Find feature (Edit > Find) in PAC Control Configure mode, I/O point references in PID loops may not be included in the list of results.

G4IDC5Q may occupy only one module position after regenerating reference counts in PAC Control

Knowledge Base - KB53137 - 7/30/2026

After regenerating reference counts (Tools > Regenerate Reference Counts) in PAC Control, a G4IDC5Q module pair may appear to only occupy one position in the Configure I/O Modules and Points dialog ...more

“Fragnesia” Vulnerability in groov EPIC and RIO

Knowledge Base - KB91515 - 6/15/2026

The “Fragnesia” vulnerability—a local privilege escalation vulnerability—could be exploited by an attacker to obtain unauthorized administrative (or root-level) privileges to...more

PAC Control strategy commands Calculate & Set Analog Offset and Calculate & Set Analog Gain return 0.0 for groov I/O or groov RIO channels

Knowledge Base - KB91448 - 6/3/2026

When calibrating analog channels on groov I/O or groov RIO modules using the PAC Control strategy Calculate & Set Analog Offset and Calculate & Set Analog Gain commands, the commands return a value of 0.0 instead of the required value.

Inspecting a communication handle variable in PAC Control Debug mode may cause a timeout error for SNAP PAC controllers and groov EPIC processors

Knowledge Base - KB86871 - 6/3/2026

When inspecting a communication handle variable in PAC Control Debug mode or any other program, you may encounter a communication timeout error with a SNAP PAC controller or groov EPIC processor running the PAC Control Engine.

GetNumCharsWaiting command with a file communication handle returns incorrect values

Knowledge Base - KB91070 - 6/3/2026

If a chart running on a SNAP-PAC-R1 (GEN2) runs the Get Number of Characters Waiting (GetNumCharsWaiting in OptoScript) command with a file communication handle, the command may incorrectly return 0 or differing (incorrect) values.

Incorrect values returned by commands that retrieve available file space on a micro SD card

Knowledge Base - KB91043 - 6/3/2026

If you request the available file space on a micro SD card through either of the two Get Available File Space PAC Control commands, the value is incorrect.

If chart calls subroutine multiple times with NULL pointer as a parameter, controller may reset

Knowledge Base - KB90966 - 6/3/2026

If a chart calls a subroutine multiple times with a NULL pointer as a parameter, the controller may reset.

Multiple UDP connection attempts with invalid connect strings may reset SNAP PAC controller

Knowledge Base - KB91425 - 6/3/2026

If a strategy uses the Open Outgoing Communication command multiple times with improperly formatted UDP connect strings, the affected controller may reset.

Writing data from a SNAP PAC controller using an FTP communication handle results in an empty destination file

Knowledge Base - KB91391 - 6/3/2026

Writing data from a SNAP PAC controller to a new destination file using an FTP communication handle may result in an empty file.

SNAP analog points converted to G1 analog points after import through PAC Manager

Knowledge Base - KB91370 - 6/3/2026

If you used PAC Manager's Import/Copy I/O Unit Image feature to create a new I/O unit from an existing SNAP PAC I/O unit configuration, PAC Manager may converts any SNAP PAC analog modules to G1 analog modules.