5 Theory of Operation
154 Keysight 34970A/34972A Service Guide
The 16 channels are divided into two banks. The banks are combined by closing
K327 for voltage and 2-wire Ohms switching. When K327 is open, the banks are
electrically independent of each other and this configuration is used for 4-wire
Ohms multiplexing where the Ohms current source is connected to channels 1
through 8 and the sense is obtained from channels 9 through 16. Relays K326 and
K328 control the connection to the analog bus for measurements using the
internal DMM.