Watlow EZ-ZONE RM Limit Module Rev C User Manual

Page 33

Watlow EZ-ZONE

RML Module

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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