UMG 96RM-PN – The communications professional
Communication from the machine to the web
To bring Ethernet from the office to the system field requires a number of enhancements; the most important is real-time capability. Depending on the application, a marketable industrial Ethernet must handle safety applications or the entire range of drive technology, right up to synchronous motion control with cycle times of less than a millisecond. You can achieve this using a clever distribution of protocols via the OSI layered system structure. This results in many solutions. One of the most common is the open standard, PROFINET, which also provides a great deal of investment protection. Existing field bus systems such as Profibus DP, Profibus PA, AS interface and interbus can be included in the existing field devices without the need to make changes.
Capturing measured data using PROFINET
PROFINET already saves costs during installation, engineering and commissioning. The operator later benefits from its ease of extension and high availability thanks to subsystems that run autonomously. Accordingly, PROFINET is represented in all applications in machinery and system construction: In the automotive industry, the paper industry, plastics processing, conveyance technology, the food industry and process engineering.
It is obvious that this communication structure can also be used for capturing machine-oriented energy data. Janitza has used the tried and tested UMG 96 range of devices as a basis to develop a PROFINET specialist: The UMG 96RM-PN – a measuring device that is much more than a standard version with a flange-mounted PROFINET interface.
UMG 96RM-PN, the PROFINET specialist
The UMG 96RM-PN is equipped with two Ethernet interfaces that conform to PROFINET IO-IRT and an integrated switch. The familiar line topologies are used to display the structure of the field bus technology in a way that complies with standards. Parameters can be set and configuration carried out completely in the Step 7® environment or the TIA portal. All measured values are displayed directly in the PLC's process data channel. Its digital inputs and outputs can be used via both Modbus and PROFINET. Two analogue inputs are available for 0-30 mA or to capture temperatures. A separate 5A current measurement channel can monitor the neutral conductor, for example.
All relevant measurements can be displayed on the device's own homepage. A REST interface enables measured values and configuration parameters to be queried from the HTTP interface. A highlight is integrated residual current monitoring (RCM), which can be used to detect insulation faults at an early stage.This increases the system availability and reduces the risk of fire.
For some years now, the classic planning model and the technology of electrical energy supply have been changing due to many external circumstances. The requirements for more efficient grids play just as large a role as the steadily increasing feed-in power from renewable energies. For the most part, these influences affect the low-voltage grid. Critical operating states and overloads can occur there, as the classically planned networks were not dimensioned for this.
Local network stations are increasingly becoming intelligent nodes: They take on tasks ranging from pure measurement to fault location, fault detection, power quality analysis, and complete remote control or even automation. Especially when retrofitting existing local network stations, the following general conditions must be taken into account:
Simple integration of measuring devices into the field bus level
Energy data capture has become increasingly important in recent years. This is less due to the cost factor itself, but more due to realising that only fine-tuned and highly temporally resolved energy data capture can enable the desired savings. To do this, the measurement technology must be integrated into existing systems – even in ongoing operation where possible.
PROFINET is ideal for this task as this standard enables it to be integrated into existing field bus systems such as Profibus DP, Profibus PA, etc. easily.
This also allows measuring devices such as the UMG 96RM-PN to be integrated into the field bus level without complications.
Simple installation reduces the costs. Furthermore, migrating from centralised to decentralised structures is possible. Additional infrastructure components are not required, as the UMG 96RM-PN already has a switch and two PROFINET interfaces on board and, therefore, enables line structures to be set up.
The energy management system can be implemented easily based on this infrastructure. PROFINET can be used to feed the data captured in real-time to a centralised location, to save it centrally in databases and to make it available for further processing in an architecture that is as open as possible.
Janitza has the relevant solutions ready – from self- sufficient software to the cloud. The users can, therefore, implement their own independent energy management or revert to the service range from Janitza.
System safety thanks to residual current monitoring
The UMG 96RM-PN does not just enable continuous capture of consumers, but also enables residual current monitoring (RCM). RCM can be used to detect faults, which would only be partially perceived – or even entirely missed – by a single system. The user is therefore able to react before fuses or residual current devices (RCD) switch off affected systems or socket power circuits. This applies in particular to quietly rising residual currents (e.g. triggered by an insulation fault), overly high operating currents and any other overloading of system parts and consumers.
However, RCM can do even more: namely reduce the risk of fire. With a sufficiently high current flow (with a dead earth short or corresponding low-resistance short) the upstream protective device disconnects the electrical consumers from the mains.
However, if the residual current is too low then the protective device will not trigger. If the recorded fault power exceeds a value of approx. 60 Watt (approx. 261 mA at 230 V), there is still a risk of fire.
By setting parameters (i.e. stipulating the typical residual current in "GOOD" condition) for the system in new condition and constant monitoring, all changes to the system state after the point of start-up can be detected. This also enables visualising creeping residual currents.
Therefore, RCM in the UMG 96RM-PN does not just increase the system availability, but also reduces the risk of fire.
100% conformity with the PROFINET standard, including PROFIenergy
The UMG 96RM-PN is certified for PROFINET and is suitable for using PROFIenergy. A PROFINET certificate attests to a response that conforms to standards in accordance with IEC 61158 within a PROFINET network and, therefore, guarantees a high standard of quality.
PROFIenergy is a profile for energy management in production systems, which is based on PROFINET. Energy consumers within the system can, therefore, be controlled using open and standardised commands. Using PROFIenergy means that external, hard-wired systems are no longer required.