User Manual

4–79Using Unscheduled Messaging
Publication 1336 FORCE–5.18 ––March, 1999
The offset specifies where in the buffer you want to start reading the
32 data points. For example, if you specify an offset of 64, the Run
File Data function returns the 32 data samples starting from data
sample 64.
If you request less than 32 trend samples, then the file data is padded
with zeros. If you request data samples past the end of the buffer,
then the file data is padded with zeros.
This data is read from the triggered trend file. Once the buffer is
filled based on the post sample number, no more data is stored and
the file does not change.
Example
In this example, Trend 1 has tripped and the message request gets the
data around the trigger condition.
10
N7:10
23456789
N7:90
PLC MSG
Write File
PLC MSG
Read File
Data Format
4191
4191 4092
3
35
4101
4101 4091 4094 4091 4097 4096 4098
N7:100
N7:100
4099 4101
4101 4099
4099
4101
4100
4102
4102
4097
4100
4095
4099
4097
4098
4100
4100
4100
4101
4099
4100 40994101 4102 4100
N7:110
Stored File Data
(continued)