Communication Considerations; About Communication Interval; Access To Non-Existent Data; When The Dx Data Type Differs From The Data Type Specified In A Command - YOKOGAWA DX1000 User Manual

Communication Considerations

About Communication Interval

Access to Non-existent Data

When the DX Data Type Differs from the Data Type Specified in a Command

DX
Type Data type INT16
Measurement INT16
channel
Computation INT32
channel
Communication FLOAT
input data
External input INT16
channel (for
reading)
14
Data Update
The DX data is updated in a scan interval. Even if a PLC accesses the data at shorter
intervals than the DX scan intervals, the data is updated only at scan intervals.
Communication Interval
A PLC should access the DX at intervals of 125 ms or longer.
* This is required to maintain compatibility with other protocols supported by the DX than
EtherNet/IP.
If non-existent data is accessed, either of the following operations occur.
• 0 is read if non-existent data is read.
• Nothing is done if non-existent data is written.
Each data on the DX has a fixed data type.
Data on the DX which includes special data accessed using the same data type is
transmitted unchanged. Data on the DX accessed using a different data has its data type
converted. The following explains the conversion rules:
Reading Data on the DX
Data type to be specified in a command
The data is read without
change.
There are limitations of
*2
INT16.
The data is converted to
INT16.
The data is read without
change.
*1 Special data will have the following values:
Data
+ Over
– Over
Skip
Error
INVALID
Burnout (Up)
Burnout (Down)
*2 The following values are used.
Data
+ Over
– Over
Skip
Error
INVALID
Less than -32768
More than 32767
Other than the above
INT32
The data is converted into
INT32 (including special data).
The data is read without
change.
The data is converted to INT32. The data is read without change.
The data is converted into
INT32 (including special data).
Value
7f800000H (+∞)
ff800000H (–∞)
ff800002H (Nan)
ff800004H (Nan)
ff800005H (Nan)
7f800006H (Nan)
ff800006H (Nan)
Value
32767
–32768
–32768
–32768
–32768
–32768
32767
The data is read without change as INT16.
FLOAT
The data is computed based on
the decimal point information set
*1
in each channel.
The data is computed based on
the decimal point information set
*1
in each channel.
The data is computed based on
the decimal point information set
*1
in each channel.
IM 04L41B01-18E