Interface Commands - Stanford Research Systems SR844 User Manual

Interface Commands

*RST
PRST
*IDN?
LOCL (?) {i}
OVRM (?) {i}
The *RST command resets the SR844 to its default configuration. The
communications setup is not changed. All other modes and settings are set to their
default conditions and values. This command takes some time to complete. This
command resets any data scan in progress. Data stored in the buffers will be lost.
The PRST command does a power-on reset. In addition to resetting the
configuration, the DSP and programmable logic are re-loaded, and the
communication ports are reset. This command takes about 5 seconds to complete;
no new commands will be recognized in the meantime.
The next command (after IFC ready becomes set again) should be OUTX i.
The *IDN? query returns the SR844's device identification string. This string is in
the format
Stanford_Research_Systems,SR844,s/n00111,ver1.00
In this example, the serial number is 00111 and the firmware version is 1.00
The LOCL command sets or queries the local/remote state. The SR844 is put into
the Local (i=0), Remote (i=1) or Local Lockout (i=2) state. These states
duplicate the GPIB local/remote states. In the Local state both remote command
execution and keyboard input are allowed. In the Remote state remote command
execution is allowed, but the keyboard and knob are locked out, except for the
Local key which returns the SR844 to the Local state. In the Local Lockout state
the entire front panel is locked out, including the Local key.
The REMOTE indicator is on in the Remote and Local Lockout states.
The Override Remote mode (below) must be set to Off in order for the front panel
to be locked out. If Override Remote is On, then the front panel is active even in
the Remote and Local Lockout states.
The LOCL? query returns 1 or 2 for the Remote and Local Lockout states. The
unit cannot return 0 (Local state) since receipt of the LOCL? query will put the
unit into the Remote state.
The OVRM command sets or queries the Override Remote mode. The parameter i
selects Off (0) or On (1).
The default mode is Override Remote On. In this mode the front panel is always
active, regardless of the Remote or Local Lockout state. (The REMOTE indicator
still indicates Remote or Local Lockout.)
To lock-out the front panel, use the OVRM0 command. In the Remote state, only
the Local key is active. Pressing the Local key will reactivate the front panel. If
the unit is in Local Lockout, the entire front panel will be disabled (including the
Local key). To reactivate the front panel, issue OVRM1 or LOCL0.
Interface 4-29
SR844 RF Lock-In Amplifier