Emerson ControlWave Instruction Manual page 133

Appendix B – Open MODBUS Interface
B.1 Supported Devices
B.2 Determining the Correct I/O Slot
Revised Aug-2015
ControlWave I/O Expansion Rack Instruction Manual
The Open Modbus Interface allows access to areas of memory in the I/O
expansion rack serving as Modbus registers and coils.
In order to determine which coil / register addresses to reference in your
Modbus commands, please refer to the tables on the following pages.
Notes:
 By default, registers are transmitted upper byte or upper word
(upper byte within a word) first.
 If, because of the requirements of your protocol, or device, you need
to change the order of transmission, please follow the instructions at
the end of this appendix.
 For information on internal mapping of particular I/O modules, see
the I/O Mapping section of the ControlWave Designer
Programmer's Handbook.
The following hardware platforms support this interface:
 ControlWave Process Automation Controller (PAC) with
ControlWave I/O Expansion Rack
 ControlWave Redundant Controller (CWRED) with
ControlWave I/O Expansion Rack
 ControlWave Redundant I/O Switcher (CW RED I/O) with
ControlWave I/O Expansion Racks
 ControlWave Micro (CWM) Process Automation Controller
with Distributed I/O System
 ControlWave CW_10, CW_30, or CW_35 controller with
CW_31 Remote I/O Rack
If you have a host ControlWave device and an I/O rack, the I/O rack's
slots are treated as slots numbered consecutively from the maximum
host I/O slot number. So to reference I/O slots in the I/O rack, add the
maximum host I/O slot number to the I/O slot number in the I/O rack.
For example, if you have a ControlWave host controller with eight (8)
I/O slots that has an attached I/O expansion rack with four (4) I/O slots,
for Modbus addressing purposes you reference the I/O expansion rack
I/O slots as slots 9, 10, 11, and 12. (See Figure B-1.)
Open Modbus Interface B-1