6.3.2 FPS Heating and Emission Regulation parameters
The following commands apply to both integrated FPS devices. It is currently not possible to configure them individually.
Therefore, no channel suffix needs to be given here.
The instruction set for the heating channels (6 and 8) are extended with the instruction “CURRent:MINimum” and
“CURRent:MAXimum”. The “Filament Ok” signal outputs a high level, if the filament measures at least a current of 90 % of the
minimum filament current “CURR:MIN”. Furthermore, the Emission regulation will not exceed the programmed minimum and
maximum filament currents.
: CONFigure:FILAment:CURRent:MINimum?
: CONFigure:FILAment :CURRent:MINimum <value>
: CONFigure:FILAment :CURRent:MAXimum?
: CONFigure:FILAment:CURRent:MAXimum <value>
Example to set the minimum current to 8 Ampere:
:CONF:FILA:CURR:MIN 8
The PID parameter of the Emission controller can be parameterized. The value is given without unit.
:CONFigure:FILAment:EMIssion:Proportional?
:CONFigure:FILAment:EMIssion:Proportional <value>
:CONFigure:FILAment:EMIssion:Integral?
:CONFigure:FILAment:EMIssion:Integral <value>
:CONFigure:FILAment:EMIssion:Differential?
:CONFigure:FILAment:EMIssion:Differential <value>
Example to set the P parameter to 1.234:
:CONF:FILA:EMI:P 1.234
The default values for the parameters of the emission control unit are:
P = 2.0, I = 0.1, D = 2.0
6.3.3 Direct Heating and Emission Regulation
For direct heating control, V
set
and I
set
values for channel 6 resp. 8 have to be given and then the channel has to be turned on. It is
possible to give an I
set
value smaller than the minimum filament current, but not higher than filament maximum current.
For emission control, additionally to the steps before, the I
set
for channel 7 resp. 9 has to be set to the expected emission current.
Afterwards, the emission channel has to be turned on. It will now take control over the heating channel and change the I
set,F
to
control the emission current. The regulation will operate in the programmed minimum and maximum filament currents, but not
exceed them. Therefore, these limits have to be choosen carefully. The minimum value must be small enough that barely
emission occurrs, the maximum value however must be small enough that no damage can happen.
SCPI protocol common instruction set | Last changed on: 2020-11-10 |
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