I have a question about excitation current flow at RTD application. Below is Fig. 9 in the LTC2983's datasheet.
I think the excitation current is sourced at CH15 in this case. This current should flow into ground somewhere in the circuit but there is no current destination (i.e. ground connection) can be seen in the circuit.
Where is the current destination? My thought is that the current flows into CH18 and/or CH20 in this case and CH18 and CH20 are connected to ground potential internally... BUT "A conversion is initiated on CH18 or CH20" is written in the datasheet so I am confusing how the device works.
Further, as I attached Fig. 18, this is excitation current rotation function. In this case the current should flow together Rsense and PT-100 both downward and upward direction. If it is correct, CH17 will be internally ground connection and the current will be sourced at CH5 (downward direction), and CH5 will be internally ground and the current will be sourced at CH17 (upward direction) vice versa. Is this correct?
Current will flow in closed "circuit" but there is no explicit explanation in the datasheet so I am wondering how the device works.
Please advise.
Satoru
