Calibration device for measuring resistance

Abstract

A calibration device for selecting calibration resistors, comprising at least one switching module (100, 100', 100", 100"'), wherein the at least one switching module (100, 100', 100", 100'") comprises:a first semiconductor relay module (10a) and a second semiconductor relay module (10b), each of which comprises:a first semiconductor relay (7) and a second semiconductor relay (9) connected in series;a third semiconductor relay (8) connected to a connection midpoint of the first semiconductor relay (7) and the second semiconductor relay (9);a housing adapted to receive the first semiconductor relay (7), the second semiconductor relay (9) and the third semiconductor relay (8); anda first input terminal (1), a second input terminal (3), a third input terminal (2), a first output terminal (6), a second output terminal (4) and a third output terminal (5) which are in the housing and are arranged so thatthat they are partially free standing outside the housing, wherein the first semiconductor relay (7), the second semiconductor relay (9) and the third semiconductor relay (8) have a first input part, a second input part, a first output part and a second output part, and within the housing one member of the pair of input parts of the first semiconductor relay (7) is connected to the first input terminal (1), the other member of the pair of input parts of the first semiconductor relay (7) is connected to the second input terminal (3), one member of the pair of input parts of the second semiconductor relay (9) is connected to the second input terminal (3), the other member of the pair of input parts of the second semiconductor relay (9) is connected to the first input terminal (1) of the second semiconductor relay (9), one member of the pair of input parts of the third semiconductor relay (8) is connected to the third input terminal (2), and the other member of the pair of input parts of the third semiconductor relay (8) is connected to the first input terminal (1),within the housing, a first member of the pair of output parts of the first semiconductor relay (7) is connected to the output terminal (6), one member of the pair of output parts of the second semiconductor relay (9) is connected to the second output terminal (4), another member of the pair of output parts of the first semiconductor relay (7) and another member of the pair of output parts of the second semiconductor relay (9) are connected to each other, a first member of the pair of output parts of the third semiconductor relay (8) is connected to the third output terminal (5), and the other member of the pair of output parts of the third semiconductor relay (8) is connected to the midpoint of the connection between the other member of the pair of output parts of the first semiconductor relay (7) and the other member of the pair of output parts of the second semiconductor relay (9), wherein each of the at least one switching module (100, 100', 100", 100"') further comprises at least one calibration resistor (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13),which are connected between the second output terminal (4a) of the first semiconductor relay module (10a) and the second output terminal (4b) of the second semiconductor relay module (10b), characterized in that the calibration means further comprises at least one selection means for selectively connecting one of the calibration resistors (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13) between a first sensor terminal (S1) and a second sensor terminal (S2), and between a first drive terminal (D1) and a second drive terminal (D2).,