Technical data

Contents of the STB register: STB xxx
Bit 7: is not used, is always set on Ø.
6: (MSS) Master Summary Bit, result by checking of the STB register with a mask
(SRE register, see below).
(RQS) Request service, for GPIB interface only, is derived from the condition of
the MSS bit according to IEEE-488.2 and is read as part of the STB register by
transmission of the command *STB? in serial operating mode according to
IEEE-488.1.
5: (ESB) Event Summary Bit, result by checking of the ESR register with a mask
(ESE register).
4: (MAV) Message Available, is set on 1 if a current massage of the unit is requested
at the output buffer.
3: is not used, is always set on Ø.
2: is not used, is always set on Ø.
1: is not used, is always set on Ø.
Ø: is not used, is always set on Ø.
Note
: When the interface GPIB is used in serial operating mode according to IEEE-
488.1 the RQS bit is readable as the part of the STB register for the PC. This
option does not exist when using interface RS-232C.
Various states and settings of the unit can be checked. For this the contents of the ESR
register are called with the help of mask (SRE - SERVICE REQUEST ENABLE REGISTER).
The single bits (except SRE bit 6, it is set on Ø always) are compared and evaluated by the
following logical equation:
MSS = (STB7
∧ SRE7) ∨ (STB5 ∧ SRE5) ∨ (STB4 ∧ SRE4) ∨ (STB3 ∧ SRE3) ∨
(STB2
∧ SRE2) ∨ (STB1 ∧ SRE1) ∨ (STBØ ∧ SREØ)
The result MSS (Master Summary Status) is saved in the STB register.
The command *SRE xxx offers the possibility of initializing the ESE register with any mask.
The value xxx has to be within the range of Ø to 255.
The current contents xxx are in the output buffer after transmitting the command *SRE?.
The contents of the register can be set on Ø by switching on the unit, by transmitting the
command *CLS or after activating the interface GPIB.
7.3.2 Description of Results
The measuring results are sent in the following format:
numeric argument of data: from x to vxx
voltage values: from x.xx to zx.xx
current values: u.xxx
where: x
•
characters from Ø to 9
v
•
characters from Ø to 2
z
•
characters from 1 to 3
u
•
characters from Ø to 4
25
Operating Instructions PN 300
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