© 2015 Thorlabs
68
Series 4000 SCPI Programmers Reference Manual
3.14.1 Programming and Reading Registers
The status system records various instrument conditions and states in several register groups.
Each register group is made up of several low-level registers called the condition register, event
register, filter register and enable register which control the action of specific bits within the
register group.
A
condition register
continuously monitors the state of the instrument. The bits in the
condition register are updated in real-time and the bits are not latched or buffered. This is a
read-only register and the bits are not cleared when you read the register.
An
event register
latches the various events from the changes in the condition register. There
is no buffering in this register; while an event bit is set, subsequent events corresponding to that
bit are ignored. This is a read- only register. Once a bit is set, it remains set until cleared by a
query or clear status (
) command.
An
enable register
defines which bits in the event register will be reported to the
Status Byte
Register Group
. You can write to or read from an enable register.
A
filter register
(= positive/negative transition register) defines which transition of the condition
register will cause an event for the event register. A set bit in the positive (negative) transition
register will lead to a set bit in the event register when a low to high (high to low) transition of
the corresponding bit in the condition register occurs.
The only registers that can be programmed by the user are the enable and the filter registers.
All other registers in the status structure are read-only registers. The following explains how to
get the parameter values for the various commands used to program enable registers.
A command to program an event enable register or a filter register is sent with a parameter
value that determines the desired state (0 or 1) of each bit in the appropriate register. An
enable register or a filter register can be programmed using binary, decimal, hexadecimal or
octal data formats for the parameter value (for a detailed description of numeric formats see
chapter 7.7.4 <NONDECIMAL NUMERIC PROGRAM DATA> of IEEE488.2-1992).
Example
The four commands program the
Auxiliary Enable Register
to the same value:
STAT:AUX:ENAB 2081
Program the
Auxiliary Enable Register
with 2018 decimal.
STAT:AUX:ENAB #H821
Program the
Auxiliary Enable Register
with 821 hexadecimal.
STAT:AUX:ENAB #Q4041
Program the
Auxiliary Enable Register
with 4041 octal.
STAT:AUX:ENAB #B100000100001
Program the
Auxiliary Enable Register
with 100000100001 binary.
The bit positions of the register (see table below) indicate the binary parameter value. For
example, if you wish to sets bits B11, B5, and B0, the binary value would be 100000100001
(where B11=1, B5=1, B0=1, and all other bits are 0). When you use one of the other formats,
convert the binary number to its decimal, hexadecimal, or octal equivalent:
Binary 100000100001 = Decimal 2081 = Hexadecimal 821 = Octal 4041
Note that the table below includes the decimal weight for each register bit. To set bits B11, B5,
and B0, the decimal parameter value would be the sum of the decimal weights for those bits
(2048 + 32 + 1 = 2081).
14
Summary of Contents for 4000 Series
Page 1: ...Series 4000 LDC40xx TED4015 ITC40xx SCPI Programmer s Reference Manual 2015 ...
Page 2: ...Version Date 3 3 08 Apr 2015 Copyright 2015 Thorlabs ...
Page 69: ... 2015 Thorlabs 3 Commands by Subsystem 67 Figure FIGURENO Status Structure ...
Page 92: ... 2015 Thorlabs 90 Series 4000 SCPI Programmers Reference Manual instrument ...