Feldbus-Koppler/-Controller • 85
Fieldbus Controller 750-806
3.2.7 Special DeviceNet Features of the Controller
3.2.7.1 Connection via the UCMM port
In contrast to the fieldbus Coupler 750-306 as a Group 2 Only Server, the DeviceNet Controller supports the dynamic connection via the UCMM port (Unconnected Message Manager Port).
For the Controller, the simultaneous set-up of 5 explicit and 5 dynamic I/O connections, i.e. the connection with 5 subscribers, is possible.
3.2.7.2 Offline Connection Set
Due to the Offline Connection Set, the fieldbus node can be addressed via the network when this node has been switched off because of a double MAC ID and is in a Communication Fault status. After being addressed, the MAC ID of the fieldbus Controller can be changed using the software.
3.2.7.3 DeviceNet Shutdown
The Device Shutdown allows the fieldbus node to log out from a control in a defined manner if the node is switched off due to internal faults. This function can be used in a targeted way in DeviceNet networks subject to very high safety requirements, such as e.g. in the chemical industry or in semi-conductor production.
3.2.7.4 Dynamic Assembly
An Assembly Object is used to group data (e.g. I/O data) to form blocks to be sent as a single message. The static Assembly allows the user to access permanently pre-programmed Assembly Instances in the fieldbus Controller. The dynamic Assembly, on the other hand, offers the possibility to set up Assembly Instances in which process data from various application objects can be configured as required.
In addition to the I/O data transmission, the dynamic assembly can also be used for a targeted selection of data which are to be transmitted explicitly via the fieldbus, or those which are explicitly not to be transmitted via the fieldbus.
Attention
To set the pysical outputs with the PFC either use the dynamic assembly or the instance 11 of the static assemblies. With this, you do not enter the physical outputs into the mapping in order to prevent the output data from being transmitted and temporary overwritten by the fieldbus.
Further information
You can find more details in chapter 5.6.2.2.2 "Dynamic Assembly".
WAGO-I/O-SYSTEM 750
DeviceNet
86 • Feldbus Coupler/Controller
Fieldbus Controller 750-806
3.2.7.5 Change MAC ID by SW
The MAC ID of the Controller can be changed via the network using the software (e.g. WAGO NETCON, RS NetWorx). For this purpose, the node address is stored in non-volatile memory. Should the address set at the DIP switch differ from the one set via the network using the software, the I/O LED changes its colour to orange.
To reset the software default address, the invalid address 64 is entered in class 3, instance 1, attribute 1.
Subsequently, the Controller has its MAC ID that is set at the DIP switch.
3.2.7.6 Heartbeat
The heartbeat function permits a node to cyclically transmit a so-called heartbeat message and, in this manner, to signal its communication ability to all members in the network.
If a responsible heartbeat consumer does not receive a message within a predefined time (Heartbeat Consuming Time), this is registered as a heartbeat fault. The relationship between producer and consumer of a Heartbeatmessage can be configured by entries in the object directory, so the time between two Heartbeat messages can be entered in Class 0x01, Instance 1, Attribut ID 10 (0x0A).
3.2.7.7 Bit-Strobe
The bit strobe I/O connection is always a 1 to n multicast connection.
In other words, a master can reach with its message all slaves supporting the bit strobe command. The transfer takes place at the same time. In this manner it is possible to synchronize the slaves.
The length of this master message is limited to 8 bytes. Each node address in the net is assigned a bit within the 8 data bytes. The reaction of the slave which bit is set is specific to the application. The reaction has to be defined and it has to be known by the PLC. With its answer, each slave can return 8 bytes of data. The order of the answers depends on the reaction time of the single slave and, in addition, it depends on the particular node address. If all slaves would reply to the Bit-Strobe command at the same time, the order of sending on the CAN bus would be determined by the node address (bit arbitration).
Further information
You can find more details in chapter 5.6.2.2.1 "Bit-Strobe".
WAGO-I/O-SYSTEM 750
DeviceNet