Siemens SITRANS F Series, Руководство по эксплуатации, Страница: 134 / 362

Modbus communication
A.8 Access control
SITRANS F Ultrasonic flowmeters FST030 (Modbus)
132
Operating Instructions, 08/2017, A5E37367739-AC
Byte count 1 byte 62
Slave ID 1 byte Sensor device type
0: SITRANS FC
Run indicator 1 byte 255: Running
Manufacturer name 12 bytes SIEMENS
Product name 32 bytes SITRANS F
Product firmware
version
16 bytes -
CRC 2 bytes
A.8 Access control
Access control manages whether the Modbus master is allowed to modify device
parameters. Reading of parameters is always possible. The general access control rules are:
● The Modbus interface has an access level that can be changed by providing PIN
information via the Modbus register 8292 (User PIN) or 8293 (Expert PIN).
● Each parameter has a protection level assigned that specifies the required access level to
modify the parameter via the Modbus interface.
● If the access level of the Modbus interface is lower than the protection level of the
parameter that is desired to be modified, then the attempt to modify the parameter is
rejected by the device.
If the device is defined as a custody transfer (CT) device and the CT write protection DIP
switch is ON (locked), the device will deny all writes to CT parameters independent of the
access control.
Table A- 7 Access control
Access level Description
Read only The Modbus master is not able to modify the device configuration (setup parameters).
The Modbus master is only able to execute the command, to reset PINs.
This is the default level of the Modbus interface.
User The Modbus master has to provide the correct user PIN with Modbus register 8292 to reach this ac-
cess level.
The Modbus master is able to modify a subset of the device configuration.
Expert The Modbus master has to provide the correct expert PIN with Modbus register 8293 to reach this
access level. The Modbus master is able to modify the configuration of the device.
If an incorrect user PIN or an incorrect expert PIN is entered, or if the device does not
receive any request within 10 minutes, the device resets the access level to read only.