User`s guide

7-40 Agilent 4155C/4156C User’s Guide Vol.2, Edition 6

Measurement Units and Functions

Zero Offset Cancel

The 4155C/4156C has zero offset cancel function. This function allows you to

minimize measurement error (offset) caused by resistance and leakage current of

cables, prober, and so on.

You can use the zero offset cancel function for:

• low current measurement (measurement range ≤ 10 nA) by SMUs.

• differential mode V measurement by VMUs.

To Measure Offset Data

To measure the offset data, do following:

1. Open the measurement terminals at the cable end of the device side.

2. Select the measurement range in the MEASUREMENT RANGE table on the

MEASURE: MEASURE SETUP screen. See Table 7-25 for the ranging mode

available.

3. Press green key and

Stop front-panel key in this order. The ZERO CANCEL field

is automatically set to ON, and offset data is measured. This data is used for the

offset cancel.

Allowable offset value is shown in Table 7-26. If offset data is too large, offset

measurement for this measurement path is not performed. For this path, an * is

marked in the ZERO CANCEL table. Then the previous data is used for the

offset cancel. The initial offset data is 0.

NOTE During offset measurement, integration time is automatically set to specified time or

medium, whichever is longer. After offset data measurement, integration time

returns to same setting as before the offset measurement was performed.

NOTE After you perform the offset measurement, if you change the ranging mode to 10 nA

limited auto or 10 nA fixed and you try to perform the offset measurement again, the

offset data is not measured for this unit. But the previous offset data is effective. So

the offset cancel can be performed for this unit using the old offset data.