
COMMUNICATION
MULTI GAUGE CONTROLLER
The data link layer includes the following properties/behaviours:
• identi ication of the Slave device address,
• detection of beginning/end of a frame,
• generation of CRC- checksum (Modbus RTU),
• transmission/reception of ”time-out” messages,
• detection of buffer thrashing,
• detection of frame errors,
• detection of line idleness.
. .
INTERFACE CONFIGURATION
There are four communication interfaces - RS
, RS
, Ethernet and Pro iNet (option).
For standard MG devices with a display, selection of interface, preview and change of its param-
eters is available in the menu, and their complete con iguration is described in subchapter . . .
In case of a device without a display ( BlackBox) communication over Modbus RTU protocol is exe-
cuted always with the same parameters (baudrate
bps, data bits, stop bit, no parity), and
the transmission channel (RS
, RS
, Pro iNet(option)) is selected by means of jumpers on the
device rear panel. The description is in point of subchapter . . .
Communication over Modbus TCP protocol is con igured using relevant commands of the Modbus
RTU protocol.
Communication in the Pro iNet(option) network is available through the interface described in
chapter . . Transmission is executed as encapsulation of the Modbus RTU protocol frame in the
Pro iNet frame. This means that the MG is visible in the network as a standard device compatible
with the Pro iNet standard and an IP address is assigned to it. Communication, however is executed
by formulating appropriate queries compatible with the Modbus RTU protocol and sending them
in a frame of the Pro iNet protocol to the Slave device. In the sent frame user should to include the
address setted up on the jumpers of the device rear panel (according to the Modbus RTU protocol).
This is a difference in relation to communication via the Ethernet interface, where the device is
unequivocally identi ied only through an IP address.
It is recommended to make all the settings of the communication interface be-
fore connecting device to the Ethernet or EIAxxx network.
It is not necessary, however, the MG default settings may cause con licts with
the devices already connected to the network.
In the Modbus RTU protocol there is only one parameter - device address. In
case of the Ethernet network there are several other parameters: IP address,
subnet mask, network, default gate address and DHCP.
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