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using SCPI commands. A thread waiting for an *OPC? response does not block the
GUI or the communication with other instruments.
A.3 Status reporting system
The status reporting system stores all information on the current operating state of the
instrument and errors which have occurred. This information is stored in the status reg-
isters and in the error queue. You can query both via RS-232, USB, GPIB or LAN inter-
face (STATus... commands).
A.3.1 Structure of a SCPI status register
Each standard SCPI register consists of 2 or 3 parts (Event, Condition and Enable reg-
ister). Each part has a width of 16 bits and has different functions. The individual bits
are independent of each other, i.e. each hardware status is assigned a bit number
which is valid for all 2 or 3 parts. Bit 15 (the most significant bit) is set to zero for all
parts. Thus the controller can process contents of the register parts as positive inte-
gers.
Depending on the value of the read register, you can draw conclusions on the current
status of the device. For example, when the unit operates in constant voltage, the
result of the returned ISUM register is a decimal "2" which corresponds the binary
value of "0000000000000010".
Any part of a status register system can be read by query commands. A decimal value
is returned and represents the bit pattern of the requested register. Each SCPI register
is 16 bits wide and has various functions. The individual bits are independent, i.e. each
hardware status is assigned to a bit number.
Bits 9 to 12 are still "free" resp. unused (always return a "0"). Certain areas of the reg-
isters are not used. The SCPI standard defines only the "basic functions". Some devi-
ces offer an advanced functionality.
Description of the status register parts
The SCPI standard provides two different status registers:
User Manual 1179.2531.02 ─ 04
Additional basics on remote control
Status reporting system
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