21
IM 04L51B01-18EN
Communication Considerations
About Communication Interval
Data Update
The GX/GP data is updated in a scan interval. Even if a PLC accesses the data at shorter
intervals than the GX/GP scan intervals, the data is updated only at scan intervals.
Communication Interval
A PLC should access the GX/GP at intervals of 100 ms or longer.
* This is required to maintain compatibility with other protocols supported by the GX/GP
than EtherNet/IP.
Access to Non-existent Data
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.
Special data
Special data will have the following values:
Channel status
Data type
Integer (Int)
Floating (Float)
+Over, +Burnout
Maximum expressible value
+
∞
–Over, –Burnout
Minimum expressible value
–
∞
Example: Channel status is “–Over”
Data type
Output value
Int16
–32768 (0x8000)
Int32
–2147483648 (0x80000000)
Float
–
∞（0xff800000）
Writing Data to the GX/GP
Input value
GX/GP value
More than 99999999
+Over
–9999999 to 99999999
The data is written without change.
Less than –9999999
–Over
Summary of Contents for Vigilantplant SMARTDAC+ Series
Page 31: ...Blank ...
