Interface/Protocols - Bender ISOMETER isoUG425 Operating Manual

Function

3.2.13 Interface/protocols

The ISOMETER® uses the serial hardware interface RS-485 with the following protocols:
• BMS
The BMS protocol is an essential component of the Bender measuring device inter-
face (BMS bus protocol). Data transmission generally makes use of ASCII characters.
• Modbus RTU
Modbus RTU is an application layer messaging protocol and it provides Master/Slave
communication between devices that are connected altogether via bus systems and
networks. Modbus RTU messages have a 16-bit CRC (Cyclic Redundant Checksum),
which guarantees reliability.
• IsoData
The ISOMETER® continuously sends an ASCII data string with a cycle of approximate-
ly 1 second. Communication with the ISOMETER® within this mode is not possible
and no additional transmitter may be connected to the RS-485 bus cable. The ASCII
data string for the ISOMETER® is described on
The parameter address, baud rate and parity for the interface protocols are configured in
the "out" menu.
With "Adr = 0", the menu entries baud rate and parity are not shown in the
menu and the IsoData protocol is activated.
With a valid bus address (i.e. not equal to 0), the menu item "baud rate" is
displayed in the menu. The parameter value "---" for the baud rate indi-
cates the activated BMS protocol. In this case, the baud rate for the BMS
protocol is set to 9,600 baud. If the baud rate is set unequal to "---", the
Modbus protocol with configurable baud rate is activated.
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isoUG425_D00220_02_M_XXEN/05.2018