pizzato ST G 2 Série Mode D'emploi page 7

Activation areas for SM G•T, SM D•T, SM L•T actuators
(mm)
25
20
15
10
5
-20 -15 -10 -5 0 5 10
Activation areas for SM E•T actuators
(mm)
30
25
20
15
10
5
-20 -15 -10 -5 0 5 10
Legend:
Rated operating distance s (mm)
n
Rated release distance s (mm)
nr
Note: The progress of the activation areas is for reference only; the possible applica-
tion on metal surfaces can reduce the operating distances.
5 OPERATION
5.1 Definitions
States of the sensor:
- OFF: sensor off, not powered.
- POWER ON: state immediately following switch on, during which the sensor carries out
internal tests.
- RUN: state in which the sensor is in normal operation.
- ERROR: safety state in which the safety outputs are disabled. Indicates presence
of a failure, either internal or external to the device, such as for example:
- a short circuit between the safety outputs (OS1, OS2);
- a short circuit between a safety output and ground, or
- a short circuit between a safety output and the supply voltage;
To exit this state, the sensor must be restarted.
- The EDM External Device Monitoring function (where present) is a function which al-
lows the device to monitor the state of external contactors. Activation and deactivation
of external contactors must follow the ST sensor safety outputs within a predefined
time period (see paragraph TECHNICAL DATA).
5.2 General operation description
f2
I3 /
f4
EDM
IS1
f1
f3
IS2
f0
LED
CONTROLLER
LED
A1 A2
RGB
the actuator is sufficient;
- in versions with safety inputs IS1 and IS2 (ST G•3••••, ST G•4••••, ST G•7••••, ST G•8••••),
presence of the actuator and activation of inputs IS1, IS2 are checked;
- in versions with EDM (ST G•5••••), presence of the actuator, activation of inputs
IS1, IS2, and presence of the feedback signal of the external contactors are checked.
In the RUN state, function f0 carries out internal test cycles in order to identify any
failures. Detection of any internal error switches the sensor to "ERROR" state (LED
illuminates red, continuous or flashing) to allow immediate deactivation of the safety
outputs by the f3 function. The ERROR state can be reached also where short-circuits
between the safety outputs (OS1, OS2), or a short circuit of an output towards ground
or towards the supply voltage, are identified. In this case also, the f3 function deac-
tivates the safety outputs and the error state is indicated by the corresponding LED
blinking frequency.
The O3 signalling output, depending on the version selected, activates or deactivates
during the RUN state corresponding to detection of the actuator within the activation
area, independently of the state of any IS1 and IS2 inputs.
The f4 function monitors the actuation state of input I3 (versions ST G•4•••• and
ST G•8••••) or EDM (versions ST G•5••••):
- in the versions with I3 input for actuator programming, when the input is active and
the device is in RUN state, the f4 function enables the actuator programming state
(see paragraph REPLACEMENT OF THE ACTUATOR);
- in the versions with EDM input, the f4 function verifies the coherence of the EDM
signal during state changes and when the safety outputs are off (see paragraph DE-
SCRIPTION OF OPERATION IN VERSIONS WITH EDM INPUT).
The information derived from the states of functions f0, f1, f2, f3, f4 is processed, and
communicated to the user via the illumination sequences and colours of the external
(mm)
25
20
15
10
5
15 20 -20 -15 -10 -5 0 5
(mm)
(mm)
30
25
20
15
10
5
15 20 -20 -15 -10 -5 0 5
(mm)
Following correct installation in accordance
with these instructions, the sensor can be
powered. The diagram shows the logic func-
tions which interact inside the sensor.
In the initial POWER ON state, the sensor
f0 function carries out an internal self diag-
nosis. When this terminates successfully,
the device switches to the RUN state. If the
O3
test is not passed, the sensor enters the ER-
ROR state.
OS1
The RUN state is the normal operation
state: the f2 function checks the presence
OS2
of the actuator within the safety activation
area.
The f3 function enables safety outputs OS1
and OS2 according to the sensor version:
- in versions without safety inputs IS1 and
IS2 (ST G•2••••, ST G•6••••), presence of
device RGB LEDs, as described in paragraph OPERATING STATES.
5.3 Description of operation in versions with IS1 and IS2 safety inputs (articles
ST G•3••••, ST G•4••••, ST G•5••••, ST G•7••••, ST G•8••••)
The f1 function evaluates the state of inputs IS1, IS2.
The IS1 and IS2 inputs are monitored not only for their state, but also for their coher-
ence: generally the inputs are actuated simultaneously. In the event of deactivation of
10 15 20
just one of the two inputs, the sensor deactivates the safety outputs and signals an
(mm)
inconsistent state of the inputs via the corresponding LED illumination sequence (see
paragraph OPERATING STATES).. Both inputs must be deactivated, for subsequent
reactivation, so that the safety outputs can be reactivated.
5.4 Description of operation in versions with EDM input (articles ST G•5••••)
The f4 function carries out a check of the NC contacts of contactors or forcibly guided
relays controlled by the safety outputs of the sensor itself; this check is carried out by
the sensor monitoring the EDM (External Device Monitoring) input. When the safety
inputs are active and the actuator is in the activation zone, the safety outputs are
10 15 20 activated only when the EDM input is active. When the safety outputs are activated,
(mm)
the device checks that the EDM input deactivates within the time t
outputs are deactivated, the device checks that the EDM signal reactivates within the
time t .
EDM
If the maximum time t
ing (where active) the safety outputs, and indicating the error via the corresponding
LED illumination sequence (see paragraph OPERATING STATES).
5.5 Connection in series with safety modules
Where a sensor with no EDM input is used, the OS1 and OS2 safety outputs must be
connected to a safety module or to a safety PLC.
The device also has an O3 signalling output that is activated (in articles ST G•2••••,
ST G•3••••, ST G•4••••) or deactivated (in articles ST G•6••••, ST G•7••••, ST G•8••••)
when the corresponding guard is closed. Depending on the specific requirements
of the implemented system, this information can be managed by a PLC, or a
programmable Pizzato Elettrica CS MP series safety module. This enables control of
both safety and signalling outputs.
Connection example
with safety module and PLC
It is possible to install multiple cascade-connected sensors, up to a maximum of 32
devices, whilst maintaining safety category 4 / PL e according to EN ISO 13849-1 and
integrity level SIL CL 3 according to EN 62061.
Check that the PFH and MTTFd values of the system consisting of the cascade of de-
vices and the entire safety circuit meet the requirements of the SIL/PL level requested
by the application.
For this connection type, the following warnings must be observed.
- Connect the inputs of the first device in the chain to the supply voltage.
- The OS1 and OS2 safety outputs of the last device in the chain must be connected
to the safety circuit of the machine.
- Where a safety module is used, check that the properties of safety outputs OS1/
OS2 are compatible with the safety module inputs (see paragraph INTERFACING).
- Respect the stray capacitance limits on the output lines indicated in the electrical
data (see paragraph TECHNICAL DATA).
- Check that the response time of the cascade meets the requirements of the safety
function to be implemented.
- The activation time of the cascade must be calculated taking into account the re-
sponse time of every single device.
The maximum number of 32 cascade-connected devices also depends on the
lengths and cross-sections of the wires used between the devices. Our technical
support service can help you with calculating the maximum distances and minimum
cross-sections of the wires to be used, for correct operation of cascade-connected
devices (see paragraph SUPPORT).
7/20
is exceeded, the system goes into ERROR state, deactivat-
EDM
Connection example
with programmable safety module
+ Vcc
IS1 IS2
ST •••••••
O3
OS1 OS2
IS1 IS2
ST •••••••
O3
OS1 OS2
IS1 IS2
ST •••••••
O3
OS1 OS2
Ixx Ixx
Pizzato Elettrica
PLC
CS series
safety module
. When the safety
EDM
+ Vcc
IS1 IS2
ST •••••••
O3
OS1 OS2
IS1 IS2
ST •••••••
O3
OS1 OS2
IS1 IS2
ST •••••••
O3
OS1 OS2
Ixx Ixx
Pizzato Elettrica
CS MP series
programmable safety module