HIMA HIMax X-MIO 6 01, Manual, Page: 13 / 72

X-MIO 7/6 01 3 Product Description
HI 801 305 E Rev. 5.00 Page 13 of 72
3.1 Safety Function
The module monitors the rotation speed of a turbine, independently of the HIMax overall system
and the user program. The module trips the turbine via the digital outputs .
Depending on the measuring input, the module determines the rotation speed and direction of a
sensor (pulse generator) with safety-related accuracy. To determine the rotation speed, one
turbine is equipped with three sensors. The rotation speed values calculated for the three
sensors are used for a 2oo3 evaluation and thus for calculating the rotation speed of the
turbine.
The module performs a 2oo3 evaluation of the digital input signals and provides the result to the
safety-related processor system and the user program.
The module ensures the outputs' safety function using three switches connected in series for
each channel. This ensures that each output is two-fault-tolerant with respect to the switch.
Each switch of a channel can be individually switched off either via the system bus (I/O bus) or
via the second independent shutdown function (watchdog).
The safety function is performed for the inputs and outputs in accordance with SIL 3, with the
exception of the relay output, which is processed as a potential-free signaling contact
(changeover).
3.1.1 Reaction in the Event of a Fault
If the safety-related processor system of the module detects a module fault during operation, the
module adopts the safe state:
 0 is output for the
Rotation Speed
parameter and 0 (0 = unequal) for the
Rotation Sense
parameter.
 All the assigned input variables transmit the initial value to the user program. The initial
values must be set to 0 to ensure that the input variables transmit the value 0 to the user
program if a fault occurs.
 All the outputs are de-energized in accordance with the de-energize to trip principle.
If the system bus fails, the outputs are de-energized. The module activates the
Error
LED on the
front plate.
3.2 Scope of Delivery
The overspeed trip module must be installed on a suitable connector board to be able to
operate. If FTAs are used, system cables are required to connect the connector board to the
FTAs. Connector boards, system cables and FTAs are not included within the module's scope
of delivery.
The various connector boards are described in Chapter 3.6, the system cables in Chapter 3.7.
The FTAs are described in separated manuals.