Hart - Siemens Simatic RTU303xC Series Operating Instructions Manual

Modbus TCP
● Active
Activates the Modbus gateway of the RTU. This makes it possible for a master (e.g.
SIMATIC PDM) to access the "HART" type field devices connected to the RTU. Field
devices can thus be configured and put through remote diagnostics via VPN.
Procedure:
If this option is selected, requests of the "Modbus TCP" type are translated by the RTU
into "Modbus RTU" and forwarded to the connected Modbus RTU field devices. The
responses are then converted back into Modbus TCP and sent back to the master.
● Port number
Port number of the Modbus gateway in the RTU. The port can only be reached via the
LAN or VPN. Default: 502
4.20.3

HART

HART
Here you set the following parameters:
● Primary Master
When enabled, the RTU is the primary master and another master can take over the role
of the secondary master.
When disabled, the RTU is the secondary master and another master can take over the
role of the primary master.
● Minimum number of preambles
Specifies the minimum preamble number when sending own requests to the RTU.
– Range of values: 5 ... 20
● Maximum number of retries
Enter the maximum number of times a frame that has not been answered positively is
repeated.
– Value range: 0 ... 7
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
Configuration (WBM)
4.20 Extension board
203