Control Techniques UD70, User Manual

Page: 74 / 154

UD70
Issue code: 70nu2
6-14 Serial communications
Mode 12 Reserved
Mode 13 Modbus – RTU (slave mode only)
Mode 14 Modbus – ASCII (slave mode only)
The Modbus RTU and ASCII slave modes support the functions Read
Multiple Registers, Preset Single Registers and Preset Multiple Registers.
This mode limits the number of consecutive registers to 20, and the node
address range is limited from 11 to 99.
Contact your local Drive Centre for information about the Modbus
Protocol.
Note
There is minimal data integrity checking with modes 2, 3
and 4.
Using Modes 2 and 3
UD70 operating in Mode 2 UD70 operating in Mode 3
Source
Scale
±16000
Any parameter Serial link
Destination
Any parameter
Scale
#xx.xx
Functions of Modes 2 and 3 Functions of Modes 2 and 3
Using Modes 6, 7, 8 and 9
In Modes 6, 7 or 8, it is possible to use the
UD70
as an
ANSI
master device
controlling other
UD70
modules,
MD29
cards, Drives or other
ANSI
compliant
devices. This facility may alleviate the need for a custom computer or
PLC
to control a system or process. When an I/O Box is used, there may be no
need for a
PLC
in a system.
Modes 6 to 9 also allow you to create custom serial protocols which you
may use for communicating with non-
ANSI
compliant devices such as
intelligent display modules, etc.
The
ANSI RS485
port is buffered as follows:
Receive: 60 bytes
Transmit: 25 bytes