The SMARTDAC+ GX90XA analog input module can be a semiconductor relay scanner type (suffix code /U2) or electromagnetic relay type (suffix code /T1), but what's the difference?

Compared to the electromagnetic relay scanner type, the semiconductor relay scanner type (suffix code /U2) has high resistance, and although it may be affected by noisy environments, it can be used semipermanently at high speeds.
Compared to the semiconductor relay scanner type, the electromagnetic relay scanner type (suffix code /T1) has low internal resistance, and can be expected to resist the effects of noise if used within lifespan and speed limitations.