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Appendix A
Fixed Formats
Any Query (
can range up to 65,535 always returns five digits, so zero would be returned as
following command descriptions, leading zeros are included. They are not, however, required when
entering the command.
Conflict Errors
Some combinations of commands and parameters can be sent to the unit that are out of range for a
particular configuration or inconsistent with other commands. For instance, specifying a Scan Interval
(
) command to less time than the unit can acquire scans results in a conflict error:
I
PRINT#1,"OUTPUT07;C1-992,I00:00:00.0,00:00:00.0X"
A conflict error lights the ERROR indicator LED on the scanning unit and returns an E4 when queried
with the Error Query (
command. For instance, in the example above, the scan interval defaults to the fastest possible scan
interval for the number of defined channels.
Command Interpretation
As commands are received by the unit, they are interpreted in the order in which they are received.
Some commands are immediate, which means they immediately take effect. Other commands are
deferred and have no effect on device operation until the Execute (
Immediate & Deferred Commands
The immediate and deferred commands applicable to ChartScan/1400 are listed in a table on the
following page.
An example of an immediate command is Set Digital Outputs (On), which immediately chooses the
digital output line which is being referred to.
An example of a deferred command is Set Data Format (
format used for channel data when
desired effects are recorded in internal temporary registers. As additional deferred commands are
interpreted, their effects are added to these registers, possibly overwriting earlier effects. Finally, when
is interpreted, the temporary registers are examined in the execution order described below. If two
X
deferred commands that do not affect the same function are received before the Execute (
they take effect in the execution order described below. If a deferred command is sent multiple times
within a command line, the last occurrence of the command will take precedence. Note that a
command line is terminated by the
be as specified by the
If an error is detected during command processing, commands are ignored up through and including the
next execute command. Thus, any immediate commands after the error, (and all deferred commands)
are ignored. For example, the command line
the error
The deferred commands
have no effect.
Deferred commands help reduce the effects of errors and improve synchronization of command
execution. The primary advantage of deferred commands is that they are executed as a group, either all
or none. If any errors occur, deferred commands have no effect and the device is left in a consistent
state instead of a partially modified, inconsistent state.
ChartScan User's Manual
)command or Status (
?
) command. Some conflict errors result in a default value for a conflicted
E?
command. The
F1,3X
only executes the
, because it is an immediate command that occurred before the error.
AA
O0
T1,1,0,0
) command returns a fixed format. For instance, any option that
U
), which determines the input and output
F
is interpreted. As deferred commands are interpreted, their
X
. For example, if
X
F1,1 F1,3X
command is overridden and never takes effect.
F1,1
T1,1,0,0O216,0,25, 255AAT3,7 K20 X
and
and the immediate command
T3,7,0,0
API Commands
. In the
00000
) command is interpreted.
X
)command,
X
is sent, the data output format will
containing
after the error
K20
A-3
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