User guide

Watlow EZ-ZONE

PM PID Controller • 34 • Chapter 4 Home Page

Range

Within this column notice that on occasion there will be numbers found within parenthesis. This number

represents the enumerated value for that particular selection. Range selections can be made simply by writ-

ing the enumerated value of choice using any of the available communications protocols. As an example, turn

to the Setup Page and look at the Analog Input [`Ai] menu and then the Sensor Type [Sen] prompt. To turn

the sensor off simply write the value of 62 (off) to Modbus register 368 and send that value to the control.

Modbus RTU Protocols

All Modbus registers are 16-bits and as displayed in this manual are relative addresses (actual). Some legacy

software packages limit available Modbus registers to 40001 to 49999 (5 digits). Many applications today

require access to all available Modbus registers which range from 400001 to 465535 (6 digits). Watlow con-

trols support 6 digit Modbus registers. For parameters listed as float notice that only one (low order) of the

two registers is listed, this is true throughout this document. By default the low order word contains the two

low bytes of the 32-bit parameter. 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 360. Because this parameter

is a float it is actually represented by registers 360 (low order bytes) and 361 (high order bytes). Because the

Modbus specification 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 [ hi-

lo].

Note:

With the release of firmware revision 7.00 and above new functions where introduced into this product line.

With the introduction of these new functions there was a reorganization of Modbus registers. Notice in the

column identified as Modbus the reference to Map 1 and Map 2 registers for each of the various param-

eters. If the new functions, namely; Linearization, Process Value and Real Time Clock are to be used than

use Map 2 Modbus regis ters. The Data Map [map] for Modbus registers can be changed in the Setup

Page under the [Com] Menu. This setting will apply across the control.

It should also be noted that some of the cells in the Modbus column contain wording pertaining to an offset.

Several parameters in the control contain more than one instance; such as, profiles (4), alarms (4), analog in-

puts (2), etc... The Modbus register shown always represents instance one. Take for an example the Alarm Si-

lence parameter found in the Setup Page under the Alarm menu. Instance one of Map 1 is shown as address

1490 and +50 is identified as the offset to the next instance. If there was a desire to read or write to instance

3 simply add 100 to 1490 to find its address, in this case, the instance 3 address for Alarm Silence is 1590.

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 conjunc-

tion with the EZ-ZONE Remote User Interface/Gateway (RUI/GTW) where those protocols can be selected

as optional hardware. For this control, 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