User manual
2638A 
Users Manual 
4-8 
Table 4-3. Scan Sample Rates 
Functions 
Sample Time (s) 
Fast 
[1]
 Medium  Slow 
DC Current 
DC Voltage 
Resistance 
0.2 PLC  1 PLC  10 PLC 
AC Current 
AC Voltage 
Fixed to 10 PLC 
Frequency  Fixed to 1 PLC 
PRT 
Thermocouple 
Thermistor 
1 PLC  2 PLC  10 PLC 
Data Security 
Data security is used to secure data files that are traceable back to the user that performed 
the test (commonly referred to as test traceability). This is necessary for test 
environments and applications that require a method to guarantee that the test data has 
not been forged, changed, or tampered with, and was produced by trained, authorized 
personnel. 
If the data security setting in the Test Setup menu is set to ON, the user must select a user 
profile and enter the associated password in order to start and record a scan. The user 
information is recorded into the scan data file that contains the user profile number and 
test information. For more information on the scan data files, see “Record” on page 4-14. 
For instructions on how to change the Admin or User profile passwords, see “Change the 
Admin and User Passwords” in Chapter 2. 
When Data Security is on, Setup files are also protected. A setup file created with Data 
Security on cannot be changed or deleted except by an authorized user. 
Note 
If the guest option is used to start a scan, the user is recorded as "Guest" 
and the data file is not considered authorized and traceable. 










