RS485 User guide
Overview - 5
2.4 Modbus adapter terminal switch
Resistor termination switch
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Depending on the position of the RVT-Modbus in the Modbus line topology, the
resistor termination switch must be switched ON or OFF.
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If the RS485 Modbus adapter is one of the two ending station on the
communication line, the resistor termination switch must be switched in the ON
position. If not, it must be switched in the OFF position.
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Make sure all other Modbus stations (master and slaves) are properly connected.
[Detailed information is available in “RVT Modbus RS485 adapter – Installation and Start
up Guide”]
2.5 RVT access level
The RVT has several access levels in order to prevent unauthorized modification of all or
some of the parameters. Three levels are described here below. The access levels have
to be taken into account for parameter settings through Modbus as same rules apply.
Locking switch:
A locking switch, located at the back of the RVT allows the RVT to be locked in AUTO
mode or in MAN mode.
When the lock is set:
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A will appear in the status bar of the display.
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The editable parameters are grey
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Access to the Change mode and Commissioning menus will be denied.
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No modification can be made to the settings
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The setting values may be consulted
This access level cannot be modified by software (with RVT Touchscreen or Modbus
communication). Pressing the locking switch physically can only modify the access
permission.
AUTO/MAN mode:
The RVT has three functional modes: AUTO, MAN and SET modes.
When the AUTO or the MAN mode is set:
