IBA ibaPADU-8AI-U Compact Measurement Modules

IBA  ibaPADU-8AI-U Compact Measurement Modules

System integration

Data acquisition with TAP interface / Sniffer

In the above example, the TAP interface is used for acquiring and analyzing the trans

ferred data without interferences. It does not have to be integrated into the configuration

of the EtherNet/IP scanner (master).

The point of installation within the EtherNet/IP network is relevant. The TAP interface

always has to be integrated linearly. You can only acquire data which are transmitted at

this position in the network.

It is therefore recommended to position the ibaBM-ENetIP directly next to the scanner

(master).

32Mbit Flex protocol and ibaFOB-D network

The ibaNet 32Mbit Flex protocol (referred to as "Flex protocol") is a manufacturer-specific

data transfer protocol by iba AG. This protocol serves to transfer measurement and con

figuration data via FO connections between different iba devices. The PC cards of the

ibaFOB-D/ibaFOB-Dexp series and the ibaFOB-io-USB adapter as well as some devices

for data acquisition support this protocol.

Data amount and sampling rate

The Flex protocol works with a data transfer rate of 32 Mbit/s and supports up to 15

"Flex-capable" devices connected in a ring topology.

With 32Mbit Flex, the data amount and the sampling rate can be flexibly customized. The

data amount transferred per cycle depends on the sampling rate. Generally, the following

applies: The less data are transferred, the higher is the possible sampling rate.

For the signals to be measured, sampling rates of 500 Hz to 100 kHz can be realized,

which correspond to a timebase from 10 µs up to 2 ms. The maximum sampling rate also

depends on the acquisition device and can be found in the device manual. In ibaPDA

you can select even smaller sampling rates down to 1 Hz. This corresponds to a time

base of 1000 ms. In this case, the timebase in the Flex ring is set to 2 ms and in ibaPDA

a subsampling is carried out. Redundant data is discarded by ibaPDA.

With 32Mbit Flex, up to 4060 Bytes per cycle can be acquired and recorded depending

on the sampling rate.

For the max. possible data amount of 4060 Bytes, the cycle time (timebase) is up to

1.4 ms. In the following table, you find reference values for the relation between cycle

time and the max. transferable data amount per cycle.

Timebase

Max data amount

1.4 ms 4060 Bytes

1.0 ms

3100 Bytes

0.5 ms

1540 Bytes

0.025 ms

64 Bytes

To acquire further samples, especially if several devices are connected in a Flex ring

topology, iba recommends using the simulator integrated in ibaPDA, see chapter 9.3.

The following data types are supported: BYTE, WORD, DWORD, INT, DINT, FLOAT and

DOUBLE in Big/Little Endian format. These data amounts represent the limit values for

the overall data amount on a Flex ring that can be transferred via an FO link.

In a ring with 32Mbit Flex protocol, up to 15 devices can be connected. In the ring, all

configuration and process data are transmitted.

ibaPDA automatically detects the devices in the ring and automatically determines the

maximum possible sampling rate, depending on the type and number of the devices.

In the ring, also other 32Mbit Flex capable iba devices can be integrated, e. g. ibaPADU

S-CM like in the example above. The devices in the ring are addressed using the rotary

switch for the device address (rotary switch S2 for ibaBM-ENetIP).

The individual device in the cascade can work with different access cycles. However,

these cycles have to be an integer multiple of the smallest cycle; e.g: device #1 works

with 0.5 ms, device #2 with 1 ms, device #3 with 4 ms, etc. If the max. data rate is ex

ceeded, ibaPDA issues an error message that advices you to enhance the timebase and

decrease the data amount.

The calculation of the maximum data amount is based on the fastest device in the ring.

i.e. an increase of the cycle time of slow devices in the ring does not lead to an increased

data transfer. Only when the cycle time of the fastest device in the ring is increased, the

data amount can be increased.

 For further information about the distribution of the data amount in the Flex ring,

please see chapter 9.3.