American Magnetics 135 & 136 Liquid Helium Level Instruments (CE-Marked) - Manual (Page 56)

44 Rev. 3
Virtual Instrument Operation
IEEE-488 Virtual Instrument
with multiple devices on one GPIB bus. The exact design of the non-
exclusive operation is dependent upon the specific devices you may have
connected to the bus.
When running the VI it is important to operate the instrument
using the VI and not via the actual instrument front panel.
Otherwise, the VI and the actual instrument may not be synchronized.
The only exceptions to this rule are operation of the sampling mode toggle
switch or operation of the relay control rotary switch if manual override
becomes necessary. The sampling mode toggle switch should be set via the
front panel of the actual instrument to the mode desired by the operator.
The VI’s representation of the sampling mode toggle switch overrides any
actual front panel setting by forcing the actual instrument to perform an
immediate measurement when placed in the UPDATE position.
5.2.1 Launching and initializing the GPIB VI
First, make sure the Model 136 is connected to the GPIB bus and that the
unit is powered on. Independent of whether you use the exclusive or non-
exclusive mode of execution, the initialization method of the Model 135/
136 should be determined. To set the initialization method, scroll to the
area above the virtual front panel and observe the virtual controls as
illustrated below (the version of the Model 13X via GPIB.vi provided in
COMP13X.LLB provides inputs for the initialization method and input/
output for the configuration). The Initialize State from Instrument? switch
allows the user to select whether the instrument is initialized from the
current settings of the actual instrument or from the controls available
from the VI. If the Yes option is selected, the VI will initialize all settings
from the actual instrument. If the No option is selected, the user should