I want to connect the GX60 expansion unit to the SMARTDAC+ GM10 but error E4 appears on the expansion module. What should I do?

There is a duplicate unit number. Use the dip switches of the expansion modules connected to each unit to ensure that the unit numbers do not overlap.

For information on setting dip switches, see “Setting Up the GX90EX Expansion Module" in the First Step Guide included in the packaging.