Thermo Scientific AquaSensors
™
DataStick
™
Ethernet Communications User Guide
62
Figure 56: Part 3 of 3 of a ladder logic program that reads the Sensor Value from N20:01.
This program can be easily expanded to read the Temperature Value from N20:03 and
N20:04.
Figure 57 shows the Setup screen for the MSG instruction on rung 3. The destination
information is contained in the “This Controller” field. The “Data Table Address” is the
register in the PLC where the Sensor Value is to be stored. Note that the “Size in
Elements” is 2 because Sensor Value is a floating-point data type that occupies registers
N20:01 and N20:02 in the Ethernet product. The Channel is 0 because this is the RS-232
port on the SLC to which the ENI is connected.
Figure 57: The Setup screen for a MSG instruction in a SLC 5/03.
The source information is shown in the “Target Device” field. The Message Timeout
specifies the amount of time that the MSG instruction will wait for the Ethernet product
to respond. Because of the way the ENI has been configured, a Local Node Address of 9
corresponds to IP address 192.168.10.201.
