Watlow ez-zone pm - Modbus Memory Blocks and Assembly Details

Watlow EZ-ZONE
®
PMI Controller • 232 • Chapter 11 Appendix
Modbus - Programmable Memory Blocks
The Modbus assembly or programmable memory blocks consists of 40 pointers to the param-
eters of your choosing starting at Modbus register 40 (shown on the following page). The
pointers are 32-bits long and are stored in two sequential registers. As an example, if it is
desired to move an alias to the analog input of the PM (register 360) into pointer registers 40
and 41, a single multi-write command (0x10 function) would be used writing 360 into register
40 and 361 into register 41.
Once the parameters of choice have been dened and written to the specied pointer reg-
isters, the working registers will then represent the parameters written. In the example
above, the 32-bit oating point analog input (360 and 361) was rst written to registers 40
and 41 which in turn denes working registers 200 and 201 as Analog Input 1. As can be seen
in the far right-hand column in the graphic above, reading back registers 200 and 201 the
temperature, as detected by the rst analog input is displayed.
The screen shot above was taken from a program that can be found on the Watlow Sup-
port Tools DVD (shipped with the product) as well as on the Watlow website. On the DVD,
it can be found under "Utility Tools" and is identied as "Modbus TCP Diagnostic Program for
EZ-ZONE PM, RM and ST". A similar program can be found here as well for Modbus RTU. If it
is easier to go to the web to acquire this software, click on the link below and type "modbus"
in the search eld where both versions can be found and downloaded. http://www.watlow.
com/en/resources-and-support/Technical-Library/Software-and-Demos