Agilent Technologies 4155C User Manual page 211

Specifications
Specification Conditions:
The "supplemental information" and "typical" entries, in the following
specifications are not warranted, but provide useful information about the functions
and performance of the instruments.
The measurement and output accuracies are specified at the rear panel connector
terminals when referenced to the Zero Check terminal under the following
conditions:
1. 23 °C ± 5 °C (double for 5 to 18 °C, and for 28 to 40 °C if not noted otherwise).
2. After 40 minutes warm-up.
3. Ambient temperature changes less than ±1 °C after auto calibration execution.
4. Integration time: medium or long
5. Filter: ON (for SMUs)
6. Kelvin connection (for HRSMU, HPSMU, and GNDU)
7. Calibration period: 1 year
Agilent 4155C/4156C User's Guide Vol.1, Edition 11 8-3