Separate a macropad from the main keyboard in a remapper
Left-Hand Pad provides separate physical keys, but a computer may receive the same key event from it and your main keyboard. A global remap can therefore change both devices. If you want a keypad key to open a tool while the regular key still types normally, confirm that the remapper can scope the rule to the intended device before creating the assignment.
Can the software distinguish the two devices?
Open the remapper's device information or event inspection view and compare the connected inputs. Look for the documented identifiers it uses in rules. A friendly name alone may not uniquely distinguish two identical devices, and the available fields depend on the software and hardware.
The Karabiner device-condition reference describes conditions for matching devices. Use the identifiers actually reported for your setup. Do not borrow another person's values just because their keypad has a similar appearance or product description.
What happens if you use a global replacement?
Suppose both devices send an ordinary letter and the rule converts that letter into an application shortcut. Without device scoping, normal typing may invoke the shortcut too. Test this possibility in a blank document before enabling the rule during work. Keep a straightforward way to disable the experiment.
If your chosen utility cannot distinguish the devices, consider changing the hardware's emitted input through its supported configuration options. That is a different strategy from adding a device filter. Verify that the alternative input does not collide with another shortcut and remains usable in your intended applications.
How narrow should the new rule be?
Match the keypad and, where appropriate, the destination application. Check the rule's fallback when another app is active. A scoped rule may stop translating outside its target, allowing the original character through. That can be acceptable or surprising depending on where you use the pad.
Avoid remapping the whole keyboard when only one control needs a new job. Begin with a single reversible action so the effect is easy to observe. Once it behaves correctly, add other mappings deliberately and preserve a readable description of each condition.
What should you test after reconnecting?
Try the keypad's mapped action, ordinary typing on the main keyboard and the same input with another application focused. Reconnect the device and confirm the rule still matches the intended entry. Save the working identifiers with the profile, excluding unrelated machine details. The Left-Hand Pad product information describes the separate hardware; device-specific behaviour comes from the configuration path you verify.