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M880 ALL EN 2.7.2.docx
7.4. STOP
(E-STOP)
Connect the contact of the E-STOP circuit so that it commands the coil of the machine’s main line
contactor and remember that the maximum allowable current is 5A with resistive load.
Attention: In order to maintain the safety category (PLe Category 4 according to ISO 13849-1),
the STOP circuit relays must be connected in series (standard IMET pre - wiring configuration),
or else in AC applications, individually connected in series to the phase line and neutral, ONLY
for the mains power interruption (
See Example 2).
In series to the STOP relay contacts, there
must always be a 5A fuse.
7.5. SAFETY ENABLE (S-ENABLE)
The
Safety
Enable
is an additional safety function. It consists of a relay in the receiver that is
monitored by the RX logic and that can be associated with the commands sent by the transmitter,
which in case of problems, automatically stops the receiver, as shown by the LEDs status.
Example 1
(in series with control commands): The Safety Enable introduces a redundancy, which
activates the safety function in case the control command relays fail to open.
Example 3
(operating the bypass valve): The Safety Enable can command the drain valve in a
hydraulic machine, such that the machine is powered only when a control command is given.
The Safety Enable must not be associated with stable selection commands
The risk analysis and safety class are based on standard ISO 13849-1. Take good notice of the
maximum currents allowed on the relay contacts (see Chap. 12).
Example 1: Wiring of the S-ENABLE relay for AC applications
Example 2: Alternative for special applications (for LAC receivers only)