beautypg.com

Sgi source scpi command subsystem – AMETEK SFA Series Ethernet Programming User Manual

Page 106

background image

SCPI Command Operation

SG Series Programming

6-34

M550129-03 Rev K

6.13.2

SGI SOURCE SCPI Command Subsystem

The Power command and its corresponding query were added to the
Source subsystem only in SGI for power regulation (Section 6.5 contains
the Source commands that can be used in both SGA and SGI). The letter
“C” in the “SCPI” column means that the command syntax is SCPI
compliant; an “N” in the “SCPI” column means that the command syntax
is not part of the SCPI definition.

NOTE: Must be preceded by commands to set maximum voltage, overvoltage
protection and current (see Description in table below).

SOUR:POWer

:POWer?

Command

Description

SCPI

SOURce

Source subsystem.

C

:POWer

Enter a value for power regulation. This command must be used in
the following manner to avoid excess power to the load:

1) Set the output state to off using OUTP:STAT OFF
2) Program a desired voltage maximum by programming

SOUR:VOLT

3) Program a desired OVP maximum by programming

SOUR:VOLT:PROT

4) Program a desired current maximum by programming

SOUR:CURR

5) Then issue the power command for the desired number of

watts SOUR:POW

6) Engage the output using OUTP:STAT ON

After the above actions the supply should be on and regulating at the
desired power level or below. (Lower level is possible because the
load may draw less than the given power setting if the voltage or
current maximums programmed in the preceding steps cause such
limitation). Subsequently the SOUR:POW command may be
issued to adjust the power level up or down.

Power mode is easily exited unintentionally by re-programming

a voltage or current value, or issuing certain other commands that
have a material influence over the power control loop. This possibility
would cause power regulation to cease and then expose the load to
either the voltage maximum or the current maximum or both;
THIS COULD CAUSE EXCESS POWER BEING DELIVERED TO
THE LOAD.
Consequently, when using power regulation, the best
practice is to restrict SCPI command traffic to queries until such a
time power mode is to be exited altogether. The suggestion for
exiting power mode intentionally is to program the output voltage and
output current to zero using SOUR:VOLT 0.0 and SOUR:CURR 0.0
See the PROG:EXEC POWERSETTINGS
command for an alternate method for entering all the relevant
settings on a single command line.

C

:POWer?

After a SOUR:POWer programming command has been issued, this
query command returns all of the settings inherent in that command.
The return takes the following format:

w @v max, a max, v ovp

C