Configuration Of The Communication; Access To Parameters - Acyclic Messages - WEG CFW-11 User Manual

The grounding of the cable shield must be done only in one point, thus avoiding long current loops. This point is
normally the network own power supply. It is recommended that the network be powered in only one point, and
the power supply signal be taken to all devices by means of the cable. In case more than one power supply is
required, they must have the same point as reference.
2.1.3

Configuration of the Communication

In order to configure and use the DeviceNet module, follow the steps below:
With the module installed, during the recognition stage, a warning message will be displayed on the product

HMI, and the MS and NS LEDs test routine performed. After this stage, the MS LED must turn on in green.
Observe the content of parameter P0723. Check if the module was recognized. The detection is done

automatically and does not require the user's intervention.
Set the parameters as desired for the application:

Address: the address of the equipment is set in parameter P0725.

Communication rate: the communication rate is set in parameter P0726.

I/O configuration: program in P0727 the number of words to be exchanged with the network master.

This same value must be set in the DeviceNet master. For this adjustment being complete, it is
necessary to program a value different from 0 (zero) in parameters P0728 to P0739 (see item 3).
Once the parameters are set, if any of the parameters described in the previous item were changed, it is

necessary to restart the equipment.
Once the equipment is set, it is necessary to configure the communication in the network master:
EDS file: register the EDS file in the network configuration tool. The EDS configuration file is supplied in a CD

together with the product. It is necessary to observe the equipment software version in order to use an EDS
file which is compatible with this version.
I/O data setting: during the configuration of the network, it is necessary to define the quantity of I/O data

communicated between master and slave, as well as the transmission method of these data. The
DeviceNet protocol defines different methods of dada exchange, seeing that the module supports the
following methods:
Polled:
communication method in which the master sends a telegram to each of the slaves of its list

scan list
( ). As soon as it receives the request, the slave immediately answers the request of the master.
This process is repeated until all slaves are polled, restarting the cycle.
Bit-strobe:
communication method in which the master sends a telegram to the network containing 8

bytes of data. Each bit of these 8 bytes represents one slave that, if addressed, answers according to
the programmed.
Change of State:

occurs when there are changes in the values monitored/controlled up to a certain time limit. When this
limit is reached, the transmission and reception will take place even if changes have not occurred.
Cyclic: another communication method very similar to the previous one. The only difference is the

production and consumption of messages. In this type of communication, every data exchange occurs
at regular time intervals, no matter if they have been changed or not.
If everything is correctly configured, the NS LED of the module will be on in green. It is in this condition that
cyclic data exchange effectively occurs between the slave and the master of the network.
2.1.4 Access to Parameters – Acyclic messages
Besides the I/O data (cyclic) communication, the DeviceNet protocol also defines a kind of acyclic telegram
explicit messages
( ), used especially in asynchronous tasks, such as parameter setting and configuration of the
equipment.
After the registration of the EDS file in the network configuration software, the user will have access to the full
parameter list of the equipment, which can be accessed via
using an addressing based on class, instance and attribute. The table 2.6 shows how to address the
parameters of the CFW-11.
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communication method in which the data exchange between master and slave only
explicit messages
. Each parameter is accessed