Watlow EZ-ZONE RM Limit Module Rev C - Manual (Page 33)

Watlow EZ-ZONE ® RML Module • 30 • Chapter 2 Menu Conventions
true throughout this document. By default the low or-
der word contains the two low bytes of the 32-bit pa-
rameter. As an example, look in the Operations Page
for the Process Value. Find the column identified in
the header as Modbus and notice that it lists register
410. Because this parameter is a float it is actually
represented by registers 410 (low order bytes) and
411 (high order bytes). Because the Modbus specifica-
tion does not dictate which register should be high
or low order Watlow provides the user the ability to
swap this order (Setup Page, Com Menu) from the
default low/high [lohi] to high/low [hilo].
It should also be noted that some of the cells in the
Modbus column contain wording pertaining to an off-
set. Several parameters in the control contain more
than one instance; such as, alarms (16), analog in-
puts (12), etc... The Modbus register shown always
represents instance one. Take for an example the
Alarm Silencing parameter found in the Setup Page
under the Alarm menu. Instance one is shown as ad-
dress 2540 and +60 is identified as the offset to the
next instance. If there was a desire to read or write
to the same member instance 3, simply add 120 to
2540 to find its address; in this case, the instance 3
address for Alarm Silencing is 2660.
To learn more about the Modbus protocol point
your browser to http://www.modbus.org .
Note:
There are two columns shown in the menus that
follow for communications protocols identified as
CIP (Common Industrial Protocol) and Profibus.
These columns will be useful if this control is used
in conjunction with the RMA module or the EZ-
ZONE Remote User Interface/Gateway (RUI/GTW)
where those protocols can be selected as optional
hardware. For this module (RML), as a secondary
protocol beyond Standard Bus, Modbus RTU can be
ordered as optional hardware.
To learn more about the RUI/GTW point your
browser to the link below and search for keyword
EZ-ZONE.
http://www.watlow.com/literature/pti_search.cfm