Data acquisition and analysis combined in one device

Paul Boughton

The ibaBM-DPMS Profibus measurement module has been used in numerous industrial measurement applications for acquiring the signals that are cyclically exchanged via the Profibus using the ibaPDA-V6 process data acquisition system.

With the new ibaBM-DP Profibus sniffer, iba now presents the technically revised successor model offering new features. As an added benefit, the Profibus sniffer offers an advanced bus diagnosis with monitoring of the signal level and the potential drift.

Due to the ibaNet 32Mbit Flex protocol, the device offers functions like an increased number of signals, flexible configuration of the sample rate and sending output signals. The new sniffer replaces the proven previous model and assumes in the compatibility mode completely its functions.

Due to the new Flex fiber optic protocol ibaNet 32Mbit Flex, the Profibus sniffer can be configured directly via the FO connection and data can be sent by iba systems via the Profibus to automation systems. Output signals of the ibaPDA-V6 data acquisition system or the ibaLogic-V4 signal manager can be sent to the Profibus master, eg in order to transmit warning messages whenever limit values are exceeded or to transfer additional setpoint values to the control.

Dr Ulrich Lettau, CEO of iba AG, explains the advantage: "If ibaBM-DP acquires, eg, signal level and potential drift and transmits these information to ibaPDA, highly sporadic failures of the bus can be diagnosed and corrected." With 32Mbit Flex, depending on the sample rate, up to 4060 Bytes per cycle can be acquired and recorded. The sampling cycles can be selected from a range reaching from 25 µs at 65 Byte to 1,400 µs at 4060 Byte. Moreover, the sniffer offers the option of cascading. Up to 15 32-Mbit-Flex-compatible devices can be connected in a ring topology.

In addition to the data acquisition, users of the new Profibus sniffer also have access to an advanced diagnostic function. For the displays on the data acquisition system, ibaBM-DP supplies diagnostic functions like eg defective telegrams/counters per bus, error counters for slaves, signal level or potential drift. Furthermore, the sniffer keeps a Profibus-Event log book containing the bus status changes and a device log book.

In order to facilitate the use of previous models in existing installations, iba has designed the sniffer in a way that no ibaPDA software update is necessary and the existing ibaFOB cards on the PDA computer can remain in use.

Moreover, the new Profibus sniffer can be inserted - as usual - at any location in the Profibus. The 'sniffer' and 'slave' operating modes can be used separately or in combination. In the 'sniffer' operating mode, ibaBM-DP listens to the data that are exchanged for communication purposes between controller, decentral periphery and drives and hence is no active participant in the Profibus. In this mode, the sniffer does not charge any resources in the controllerl. In the 'slave' operating mode, the device is an active participant in the Profibus and can be supplied with data in a targeted way.

In redundancy mode - especially for S7-400H controllers - ibaBM-DP can listen to and acquire data from redundant Profibus lines. Hence, the sniffer monitors the telegram traffic on both Profibus drops, but only
records the active drop. The data do not need to be acquired twice.

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