33
2600T SERIES |  PRESSURE TRANSMITTERS |  OI/266/FF-EN REV. E
8  Electronics
Fault protection
The 266 PdP electronic implements the circuitry for the fault 
current protection. Whenever a fatal failure occurs and the 
current consumption increase over the 20 mA, this circuitry 
provides to disconnect the device from the bus, in order to 
preserve alive the rest of the bus that, otherwise, could drop 
down with all the other connected devices.
On board switches
On the electronic unit (behind the Local Display when installed) 
there are 4 switches, with the following functionality:
SW 1 – Replace Mode
In UP position (1) it enables the Replacement operation. It must 
be used in combination with the SW 2 that selects which part of 
the Transmitter is going to be replaced.
SW 2 – Replace Mode - details
In UP position (1) it selects the Sensor Replacement. The entire 
transmitter’s configuration data are kept valid in the 
electronics and copied into the memory of the new sensor once 
it is connected. In OFF position (0) it selects the Electronics 
Replacement. The entire transmitter’s configuration data are 
kept valid in the sensor memory and copied into the memory of 
the new electronics once it is connected.
SW 3 – Push Buttons Mode
This switch selects the type of operation executed with the 
housing push buttons located under the type plate. In UP 
position (1) it enables the push buttons for the ranging 
operation. In OFF position (0) it enables the push buttons for 
the PV bias Set/Reset operations.
SW 4 – Simulation Mode
This switch in UP position (1) enables the Standard Simulation 
feature mandatory for FF devices.
266FF can simulate diagnostic conditions by writing the error 
to be simulated into “RB_FD_SIMULATE” (index 67) or can 
simulate the value and status output of the PRTB going in input 
to the AI, by writing into “AIx_SIMULATE” (index 9).
However, this writing has effect only if the HW switch 4 has 
been previously moved in ON position (SIMUL MODE ENABLE).
Factory default configuration
The on-board switches are set by default in OFF position (0).
Therefore:
SW 1 – Replace Mode is disabled.
SW 2 – Replace Mode - details on New Electronic but with no 
effect since SW 1 is on OFF position.
SW 3 – Push Buttons Mode on OFF position (0). With this 
configuration, the external non-intrusive push buttons perform 
the PV bias Set/Reset function by default.
SW 4 – Simulation Mode on OFF position (0). The Simulation 
mode is disabled. It can be performed only when the hardware 
dip-switch is alligned to the same software functionality.