Samson 3374-11 - Setting up Modbus-RTU Communication; Protocol

34 EB 8331-4 EN
Additional functions
6.3 Setting up Modbus-RTU
communication
The electric actuator can be connected to a
control station over Modbus and can be con-
gured using TROVIS-VIEW. For this pur-
pose, the actuator with rmware version
3.10 and higher can be tted with an RS-
485 module. Various communications proto-
col (SSP or Modbus-RTU slave) are used for
various functions.
For Modbus-RTU communication, the RS-485
module (order no. 1402-1522) must be in-
serted into the actuator.
Î Excerpt from Modbus list: see sec-
tion17.2.8.
6.3.1 Protocol
− Setting:automatic
The SSP and Modbus-RTU protocols are
automatically detected: the interface pa-
rameters are xed 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 Mod-
bus-RTU protocol. All interface parame-
ters listed in 6.3 are adjustable.
General information on operating the elec-
tric actuator: see section7.
Station address (Code A64)
The station number is used to identify the
electric actuator for the Modbus-RTU proto-
col.
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 sta-
tion. Otherwise, no communication is estab-
lished.
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 communica-
tion is monitored by the bus failure monitor-
ing (timeout). After a bus failure is detected,
automatic operation is reestablished. The
time for the bus failure monitoring is adjust-
able. Set the value to 0 to deactivate bus
failure monitoring.
Note