Local Operation 
 
3-24  M370430-01  Rev B 
The alarm LED will remain illuminated until the alarm is manually 
cleared (see “Clearing Triggered and Manual Alarms” on page 3-22) 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 Table 3-4 on page 
3-21. 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 Table 3-5 for the alarm 
values associated with each maskable alarm. 
Table 3-5  Alarm Mask Bit Positions 
Over Temperature Protection (OTP) 
Over  Temperature  Protection  (OTP)  Slave 
(1700W only) 
Under Voltage Protection (UVP) 
 
The SCPI command (s) for these instructions are: 
[:]SYSTem[<channel>]:PROTection:MASK