Tektronix Keithley 2268 Series, Справочное руководство

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Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation
2268S-901-01 Rev. A / January 2015 47
The alarm LED will remain illuminated until the alarm is manually cleared (see “Clearing
Triggered and Manual Alarms” on page 45) or by turning the main output on if the alarm has
automatically been cleared.
Alarm Masking
It is possible to completely disable some alarms through the use of the alarm mask. If an
alarm is masked then this masking will prevent it from registering in the SCPI conditions
registers as well as not triggering the alarm. The alarms that can be masked are identified in
the table on page 44. Setting the bit position (1) of an alarm will result in the alarm being
enabled. Clearing the bit position (0) of an alarm will result in the alarm being
masked/disabled.
For Example:
If you wanted to enable the OTP, Foldback and UVP alarms, you would take the foldback
value of 256 and the UVP value of 1024 to get a mask of 1280. This is the value you would
send with the SCPI command.
Control of the alarm mask is only available using the SCPI command.
The SCPI command (s) for these instructions are:
[:]SYSTem[<channel>]:PROTection:MASK
The mask command takes a single parameter made up of the sum of the values for the alarms
that are to be masked. See the table that follows for the alarm values associated with each
maskable alarm.
Alarm Bit Position Value
Over Temperature Protection (OTP) 2 2
Not used 3 4
Fan 3 8
Foldback 8 256
External Shutdown 9 512
Under Voltage Protection (UVP) 10 1024
The SCPI command (s) for these instructions are:
[:]SYSTem[<channel>]:PROTection:MASK