789 
Users Manual
 
20 
Compensating for Test Lead Resistance 
Use the relative reading feature (Q on the display) to set 
the present measurement as a relative zero. A common 
use for this feature is to compensate for test lead 
resistance when measuring ohms. 
Select the Ω measure function, touch the test leads 
together, and then press r. Until r is pressed 
again, or the meter is switched to another measurement 
or source function, the readings on the display will 
subtract the lead resistance. 
Using the Current Output Functions 
The meter provides steady, stepped, and ramped current 
output for testing 0-20 mA and 4-20 mA current loops. 
Choose source mode, in which the meter supplies the 
current, simulate mode, in which the meter regulates 
current in an externally powered current loop, or loop 
supply mode, where the meter powers an external device 
and measures the loop current.  
Source Mode 
Source mode is selected automatically by inserting the 
test leads into the SOURCE + and − jacks as shown in 
Figure 7. Use source mode whenever it is necessary to 
supply current into a passive circuit such as a current loop 
with no loop supply. Source mode depletes the battery 
faster than simulate mode, so use simulate mode 
whenever possible. 
The display looks the same in source and simulate modes. 
The way to tell which mode is in use is to see which pair 
of output jacks is in use.