Mainframe Actions

The Mainframe module lets you automate interactions with mainframe terminal emulators directly from the Appian RPA actions palette. This page covers prerequisites, architecture, supported emulators, and the available action categories.

How the Mainframe module works

The Mainframe module communicates with a terminal emulator through the EHLLAPI (Emulator High Level Language Application Programming Interface) DLL. EHLLAPI is a standard IBM interface that allows external programs to interact with mainframe sessions running in a terminal emulator.

When a robotic task runs, the module calls EHLLAPI functions exposed by the emulator's DLL to read from and write to the terminal screen. The emulator must be running and connected to an active mainframe session before the robotic task starts. The module does not start the emulator or manage the mainframe session.

Prerequisites

Before using the Mainframe module, make sure the host machine meets the following requirements:

• Advanced Tier license: The Mainframe module is an Advanced Tier feature. Confirm with your account team that your license includes access.
• EHLLAPI-compatible emulator: An emulator that exposes EHLLAPI must be installed and running on the host machine. See Supported emulators below.
• Active mainframe session: The emulator must be connected to a mainframe session before the robotic task executes. The module cannot establish or manage the connection itself.
• Java 17: Required for all Appian RPA robotic task executions. See System Requirements for details.

Supported emulators

Any emulator that supports EHLLAPI is compatible with the Mainframe module. The following emulators are commonly used:

Emulator	Common DLL path
IBM Personal Communications (PCOMM)	C:\Program Files\IBM\Personal Communications\ehlapi32.dll
QWS3270	C:\Program Files\QWS3270\qwhllapi.dll
Rumba	C:\Program Files\Micro Focus\Rumba\ehlapi32.dll

Action categories

The Mainframe module organizes actions into four categories:

• Connection and Setup Actions: Connect to and disconnect from an emulator, and maximize the emulator window.
• Data Reading Actions: Find text on screen, retrieve text from the terminal, and read field values by coordinates.
• Data Writing Actions: Write input to the terminal at the cursor position, by coordinates, or by label, including secure credential input.
• Navigation and Control Actions: Move the cursor, wait for screen changes, and send special control keys.

Error handling

If your robotic task encounters an error during a mainframe action, check the execution log for details. When the error originates from the EHLLAPI interface, the log includes the error code and description.

Limitations

Keep the following limitations in mind when designing mainframe automations:

• No direct integration with specific emulators beyond the EHLLAPI standard interface.
• One mainframe session per robotic task execution. Multi-session automation is not supported.
• No task recorder integration. Mainframe actions must be added manually.
• No direct database connections to AS/400 or DB2. The module uses terminal emulation only.
• No automated emulator startup. The emulator must be running before the robotic task executes.

Migrate from the IBM 3270 Workflow Library plugin

If you currently use the community IBM 3270 Workflow Library plugin for mainframe automation, see Migrate from the IBM 3270 Plugin for a mapping of plugin actions to Mainframe module actions and guidance on updating your existing robotic tasks.

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