User manual

Series 3700 System Switch/Multimeter Reference Manual Section 13: Instrument Control Library (ICL)
3700S-901-01 Rev. C / July 2008 13-115
dmm.autozero
Remarks
This is the auto zero setting for the DMM. It applies to the selected function as
indicated by dmm.func (on page 13-137). Querying the auto zero when the selected
function does not have an auto zero setting associated with it will cause nil to be
returned.
An error is generated if command is received when dmm.func =
"nofunction". Also, an error will be generated if the value is invalid.
Changing functions with dmm.func (on page 13-137) will cause that function's auto
zero setting to take effect.
The auto zero once setting will force a refresh of the backgrounds. After doing this
once, the auto zero setting will automatically be set to "OFF". Therefore, querying the
dmm.autozero state after setting dmm.autozero to 2 generates a response of 0 and
not 2.
Example
To enable auto zero for DC volts:
dmm.func = "dcvolts"
dmm.autozero = dmm.ON
To force backgrounds to cycle once and set auto zero to OFF:
dmm.autozero = dmm.AUTOZERO_ONCE
print(dmm.autozero) 0.000000000e+000
dmm.buffer.catalog()
Function
Creates an iterator for the user-created reading buffers.
Usage
for name in dmm.buffer.catalog() do...end
Remarks
Accessing the catalog for the user-created local reading buffers allows the user to print
the names of all reading buffers in system. The entries will be enumerated in no
particular order. From this list, one may selectively delete reading buffers from the
system. For example:
for name in dmm.buffer.catalog() do print(name) end
outputs:
buf3
buf5
buf1
Now, with these buffers in the system, to delete buf1:
buf1 = nil
collectgarbage()
Key Note: Don't delete the reading buffers by doing
for name in dmm.buffer.catalog() do name = nil end
This will not delete the reading buffers from the system but make the system appear
locked up and an abort will need to be done to stop the command from running by
pressing the EXIT key on front panel. This occurs because name is a string type
variable and not a reading buffer type.