R&S ESU Series Operating Manual page 425

R&S ESU
With these two edge register parts the user can define which state transition of the
condition part (none, 0 to 1, 1 to 0 or both) is stored in the EVENt part.
EVENt part
The EVENt part indicates whether an event has occurred since the last reading, it is
the "memory" of the condition part. It only indicates events passed on by the edge fil-
ters. It is permanently updated by the instrument. This part can only be read by the
user. During reading, its contents is set to zero. In linguistic usage this part is often
equated with the entire register.
ENABle part
The ENABle part determines whether the associated EVENt bit contributes to the
sum bit (cf. below). Each bit of the EVENt part is ANDed with the associated ENABle
bit (symbol '&'). The results of all logical operations of this part are passed on to the
sum bit via an OR function (symbol '+').
ENABle-Bit = 0: the associated EVENt bit does not contribute to the sum bit
ENABle-Bit = 1: if the associated EVENT bit is "1", the sum bit is set to "1" as well.
This part can be written into and read by the user at will. Its contents is not affected
by reading.
Sum bit
As indicated above, the sum bit is obtained from the EVENt and ENABle part for
each register. The result is then entered into a bit of the CONDition part of the
higher-order register.
The instrument automatically generates the sum bit for each register. Thus an event,
e.g. a PLL that has not locked, can lead to a service request throughout all levels of
the hierarchy.
The service request enable register SRE defined in IEEE 488.2 can be taken as
ENABle part of the STB if the STB is structured according to SCPI. By analogy, the
ESE can be taken as the ENABle part of the ESR.
5.20
Remote Control – Basics
Status Reporting System
Operating Manual 1302.6163.12 - 03