Watlow Electric RUI/Gateway - Manual (Page 16)

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 16
FM 4/08
34. To better understand the following discussion and examples download and read the section
entitled “User Programmable Memory Blocks” found in the EZ-ZONE ® PM Communications
user manual.
When using the RUI/Gateway equipped with Modbus ® TCP or Modbus ® RTU and while
communicating with EZ-ZONE ® * PM controls a block of 40 pointers or 80 words has been
created to serve as the “Assembly Definition Addresses” and another group of 40 elements or
80 words has been defined as the “Assembly Working Addresses”. The Assembly Definition
Addresses are user configurable. Once configured with the Modbus
® registers of choice, the
corresponding Assembly Working Addresses assume that particular parameter as
programmed, and will then reflect that parameters actual value. What this means then is that
the user can configure a contiguous block of 40 elements or 80 words to any available
parameter of their liking. It is recommended that when doing this configuration that the
parameters data type be considered. It is much easier to set up a contiguous block of words
of the same data type.
Note:
If the user sets any of the EZ-ZONE ® PM controls back to factory defaults this assembly for
that control will set to the factory defaults as well.
35. In step 24 we defined the maximum number of words that can be read as 32. The maximum
number of words Modbus ® allows to be read at one time is 120 or 240 bytes, so all 80 words
could be read and or written to if so desired. Due to this previous entry (step 24) in order to
read the low order 40 words there were two read tags configured, 20 words each defining
them as “Low order Assembly 1 & Low order assembly2”. Likewise, the same was done for
the upper 40 words where they are defined as “High order Assembly 1 & High order
Assembly2”. The screen shot below was duplicated 3 more times simply changing the names
and addresses to create the tags mentioned above.
* The EZ-ZONE
®
ST does not support programmable memory blocks. However, any
ST parameter that is available over Modbus
®
can be accessed in a similar manner
as was described in step 29.