Example 3: Two-Hand Control; Functional Description Of Safety Functions - ABB AC500-S Safety User Manual

Safety application examples
Example 3: two-hand control > Functional description of safety functions
Function block
SF_LightCurtain_1
SF_OutControl_1
SF_EDM_Contactor_1 S_StartReset

7.4 Example 3: two-hand control

This example describes a machine where a two-hand control initiates the dangerous movement
as long as both push buttons on the two-hand control are pressed and the process provides an
enabling signal.
The dangerous movement is initiated by the closing of two subsequent contactors, which are
monitored via a feedback loop.

7.4.1 Functional description of safety functions

This example uses the following safety functions:
● By pushing an emergency stop button all hazardous movements must be stopped (via
SF_EmergencyStop). Emergency stop has the highest priority. After releasing the E-Stop
push button, a reset via S0_Reset is required.
● By pressing both push buttons of the two-hand control, the safety output is activated. The
release of any of the two-hand push buttons disables the safety output and stops the dan-
gerous motion via the contactors K1 and K2 (via SF_TwoHandControlTypeII).
● The initial state and the operational state of the connected contactors K1 and K2 are moni-
tored and if an error is detected, the safety output cannot become operational (via
SF_EDM).
● After power on of the safety or functional application, or after an emergency stop condition,
the two-hand control must be released and re-operated in order to activate the safety output
again (via SF_OutControl). In order to guarantee this for the functional application restart,
the process signal from the functional application is connected to the Activate input of the
two hand control function block THC_S2_S3 (If the application process is restarted while the
two hand control is activated, the FB goes to the state C003 signaling an error that both but-
tons are pressed at the activation, prohibiting a restart.).
In this example, only one operation mode exists.
352
Input Constant value
MaxMutingTime T#30s
S_StartReset TRUE
S_AutoReset FALSE
TestTime T#100ms
NoExternalTest TRUE
S_StartReset FALSE
S_AutoReset FALSE
StaticControl FALSE
FALSE
MonitoringTime T#30ms
3ADR025091M0208, 12, en_US
Description
The maximum muting time is monitored to
be within 30 s
Automatic reset allowed when PES is started
No automatic reset, user reset/acknowledge
necessary
The maximum test time is monitored to be
within 100 ms
The external manual sensor test is not sup-
ported.
No automatic reset allowed when PES is
started
No automatic reset, user reset/acknowledge
necessary
A dynamic change of the signal ApplCtrl1
(rising edge) is required after block activation
or a triggered safety function (S_SafeControl
= FALSE).
No automatic reset allowed when PES is
started
The maximum response time of both feed-
back signals S_EDM1 and S_EDM2 are
monitored to be within 30 ms.
2020/06/19