Operation - Pizzato Elettrica ST Series Manual

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 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 allows the device
to monitor the state of external contactors. Activation and deactivation of external contactors must fol-
low the ST sensor safety outputs within a predefined time period (see paragraph TECHNICAL DATA).
-
- in versions with EDM, presence of the actuator, activation of inputs IS1, IS2, and presence of the
feedback signal of the 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 (PWR LED continuously red) to allow
immediate deactivation of the safety outputs. 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 deactivates the safety
outputs and the error state is indicated by the OUT LED flashing red.
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 state of output O3 is displayed via the ACT LED.
5.3 Description of operation in versions with safety inputs IS1 and IS2
The f1 function evaluates the state of inputs IS1, IS2.
The IS1 and IS2 inputs of the ST sensor are monitored not only for their state, but also for their
coherence: generally the inputs are actuated simultaneously. In the event of deactivation of just one
of the two inputs, the sensor deactivates the safety outputs and signals a non-coherent condition of
the inputs via the IN LED flashing green/orange. 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
The f4 function carries out a check of the NC contacts of contactors or forcibly guided relays con-
trolled 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 activated only when the EDM input is active. When the
safety outputs are activated, the ST sensor checks that the EDM input deactivates within the time
t . When the safety outputs are deactivated, the ST sensor checks that the EDM signal reactivates
EDM
within the time t .
EDM
If the maximum time t is exceeded, the system goes into ERROR state, deactivating, where ac-
EDM
tive, the safety outputs, and indicating the error via the IN LED flashing red.
5.5 Connection with safety modules and in series
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.
It is possible to install multiple cascade-connected sensors, up to a maximum of 32 units, whilst
maintaining safety category 4/PLe according to EN ISO 13849-1 and integrity level SIL CL 3 ac-
cording to EN 62061. Check that the PFH value and MTTFd value of the system consisting of the
cascade of sensors and the safety module, 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 sensor in the chain to the supply voltage.
• The outputs of the last sensor in the chain must be evaluated by a safety module.
• Use the sensor cascade with the Pizzato safety modules (see paragraph OPERATION).
The ST series sensors can be connected, provided that compatibility is checked, to safety mod-
ules or safety PLCs that accept OSSD type signals as inputs.
• Check that the activation time of the cascade meets the requirements of the safety function to be
implemented.
• The response time of the cascade must be calculated taking into account the response time of the
actuated device (tr ) plus the response time (tr
A
sensor and the safety module.
For certain specific applications, as an alternative to connection to safety modules, it is possible to
use the ST D•5•••• version sensor with check of the NC contacts of the forcibly guided relays (K1,
K2) connected to the EDM input, installed as the last sensor in the cascade (see paragraph 4.6).
When using this functionality, consider the mandatory safety requirements in 1.2.3 annex 1 of the
Machinery Directive 2006/42/EC: "For machinery functioning in automatic mode, the starting of the
machinery, restarting after a stoppage, or a change in operating conditions may be possible without
intervention, provided this does not lead to a hazardous situation".
+
IS1 IS2
SM
ST D•310••
OS1 OS2
IS1 IS2
ST D•310••
SM
OS1 OS2
IS1 IS2
SM
ST D•51•••
OS1 OS2
K1 K2
5.2 General operation description
Following correct installation in accordance with
these instructions, the sensor can be powered. The
diagram shows the logic functions which interact
inside the sensor.
In the initial "POWER ON" state, the sensor f0 func-
tion carries out an internal self diagnosis. When this
terminates successfully, the device switches to the
"RUN" state. If the test is not passed, the sensor en-
ters the "ERROR" state.
The "RUN" state is the normal operation state: the f2
function checks the presence 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, pres-
ence of the actuator is sufficient.
in versions with safety inputs IS1 and IS2, presence
of the actuator and activation of inputs IS1, IS2 are
checked.
) of each sensor connected between the actuated
I
O3
O3
O3
EDM
5.6 Interfacing
Connections with CS AR-08•••• safety modules
Input configuration with monitored start
2 channels / Category 4 / up to SIL 3 / PL e
4/5-pole versions
A1
A2
ST
OS2
S52 S33
A1
CS
S21 S22 S35 S34
A2
Connections with CS AR-05•••• / CS AR-06•••• safety modules
Input configuration with manual start (CS AR-05••••) or monitored start (CS AR-06••••)
2 channels / Category 4 / up to SIL 3 / PL e
4/5-pole versions
A1 A2
ST
OS2
A1 S52
CS
S21 S22 S34 A2
Connections with CS AT-0••••• / CS AT-1••••• safety modules
Input configuration with monitored start
2 channels / Category 4 / up to SIL 3 / PL e
4/5-pole versions
A2
A1
ST
OS2
S31 S33
A1
CS
S21 S22 S35 S34 A2
Connections with CS MF••••0, CS MP••••0 safety modules
The connections vary according to the program of the module
Category 4/ up to SIL 3 / PL e
4/5-pole versions
A2
A1
A1
ST
OS2
Ixx Ixx
Ixx
CS
Connections with external contactors (EDM versions only)
The ST sensor in the ST D•5•••• version must be connected to contactors with forcibly guided output
contacts, as shown in the diagram below. When connected in this way, the sensor can be classified
as a control circuit device up to PDF-M (EN 60947-5-3)
A1
ST D•51•••
K1
We recommend the use of fast switching diodes connected in parallel to the
contactor coils
6/16
8-pole versions
A1 IS2
ST
OS2
S52
A1
CS
S21 S22 S35 S34
8-pole versions
A1
ST
A1
CS
S21 S22 S34
8-pole versions
A1 IS2
ST
OS2
S31
A1
CS
S21 S22 S35 S34
8-pole versions
A2
A2 A1 IS2
ST ST
OS2
OS2
Ixx Ixx
Ixx
CS
IS2
A2
EDM
OS2
K2
A2
S33
A2
IS2 A2
OS2
S52
A2
A2
S33
A2
A2
A1 IS2
ST
OS2
Ixx Ixx