Samson 3375, Mounting And Operating Instructions

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EB 8332-2 EN 7-11
Start-up and configuration
7.5.2 Modbus RTU module
The electric actuator can be connected to a control station over Modbus and can be config -
ured using TROVIS-VIEW. For this purpose, the actuator with firmware version 3.10 and
higher can be fitted with an RS-485 module. Various communications protocol (SSP or Mod
-
bus RTU slave) are used for various functions.
For Modbus RTU communication, the RS-485 module (order no. 1402-1522) must be insert-
ed into the actuator.
Î
Excerpt from Modbus list: see Annex A.
Protocol
− Setting: automatic
The SSP and Modbus RTU protocols are automatically detected: the interface parameters
are fixed internally to Baud rate 9600 bit/s, 8 data bits, no parity, 1 stop bit. The electric
actuator can exchange data with TROVIS-VIEW or the control station without switching
over. The station address and bus failure monitoring are adjustable.
− Setting: Modbus RTU
Communication is based on the Modbus RTU protocol. All interface parameters listed in
Table 7-2 are adjustable.
Station address (Code A64)
The station number is used to identify the electric actuator for the Modbus RTU protocol.
Baud rate (Code A65)
It is the transmission rate between the electric actuator and control station/computer. The
Baud rate adjusted at the electric actuator must be the same as that in the control station.
Otherwise, no communication is established.
Stop bit and parity (Code A66)
The number of stop bits and the parity are set in Code A66. The parity is used to detect data
transmission errors. The parity bit is added to the end of the string of data bits and the total
value is made up from the data and parity bit.
Bus failure monitoring (Code A67)
The external manual level of the communication is monitored by the bus failure monitoring
(timeout). After a bus failure is detected, automatic operation is reestablished. The time for
the bus failure monitoring is adjustable. Set the value to 0 to deactivate bus failure monitor-
ing.