Figure F6. Block diagram of the strainmeter control electronics. The dashed vertical line separates downhole components from those on the seafloor. Regulated voltage from the SWB powers the differential transformers (DTs) (different supplies are needed for the two types of strainmeter). Output signals from the DTs are fed to both a 16-bit analog-to-digital (A/D) converter for instrument control and to 24-bit A/D converters for data acquisition. An RS232 serial link is provided so that commands can be issued remotely (via CRM; see Fig. F13) to operate the strainmeters.