There are many factors which will affect the overall scanning speed of a DMM/switch system. The major factors include the type of the measurement, the range of the measurement, and resolution of the measurement. The effect of these and other factors related to the DMM can be better understood by considering the digital multimeter measurement cycle. In addition to these factors, relay operate times, DMM settling times, and switch settling times limit the overall speed of the system. The following benchmarks provide a good starting point to see typical scan rates for common use cases.
The benchmarking application that was used to gather the following data is attached to this document. It was created using LabVIEW 2017, NI-SWITCH 17.0 and NI DMM 17.0. It can be configured to use your desired hardware, configurations, and measurement type and run to display the DMM+Switch Handshaking Scan Rate.