Watlow Electric RUI/Gateway - Manual (Page 12)

RUI/Gateway & Modbus ® TCP
Configuration & Programming Example
Using KEPServerEX 4.0
Watlow
1241 Bundy Blvd
Winona, MN 55987
Telephone: 507-494-5656
© 2008 Watlow Electric Mfg Co 12
FM 4/08
27. This concludes the device (RUI/Gateway) configuration.
28. Tag creation. In step 5 some prompts were shown indicating further explanation would follow,
well, here we are.
The Gateway Instance and the Gateway Enable prompts must be set as shown in step 5 for
this particular network. The Gateway Instance corresponds to the address given to the PM
control and the Gateway Enable simply requires a “Yes” or “No” response.
When trying to read or write to any given member in a destination PM control it is important to
keep in mind that there is a unique Modbus
® address set aside for that member. As an
example, note that as found in the EZ-ZONE ® PM Communications user manual under the
“Operations Page” Process Value 1 (PV1) is given a Modbus ® address of 360 with a data type
of floating point. As shown in the graphic in step two of this document there are four PM
controls on the Standard Bus side of the network where each has the same address for PV1.
As read through the RUI/Gateway, if it is desired to read PV1 of PM3 the Modbus
® offset
( M;oF) must be observed and used. So, in this particular case, the appropriate address to
be read would be 410361 not 400361 where the offset as shown in step 5 for PM3 is 10000.
Based on this network configuration, if it is desired to read PV1 from each of the four PM
controls on the Standard Bus side of the network the following addresses would correlate to