Banner E-Stop ES-TN-14H5 Instruction Manual page 5

E-Stop Safety Modules with Adjustable Delay –
WARNING . . .
!
1-Channel Input
If a 1-channel E-stop button
is used, a single fault (such as a short
across the single E-stop contact or from
the contact to a secondary source of
power) can lead to the complete loss of
safety.
A 1-channel E-stop should be used
only in applications where such a fault
can be excluded, or the resulting loss
of safety cannot result in serious injury
or death (Safety Category 2, 1 or B;
see page 3).
If a 1-channel E-stop is used, separate
the wires from each other by routing
them through separate wireways
or conduit in order to increase the
reliability of the interface.
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E-Stop Switch Requirements
As shown in Figure 3, the E-stop switch must provide one or two contacts which are
closed when the switch is armed. Once activated, the E-stop switch must open all
its contacts, and must be returned to the closed contact position only by means of
a deliberate action (such as twisting, pulling, or unlocking). The switch should be a
"positive-opening type," as described by IEC 60947-5-1. A mechanical force applied
to such a button (or switch) is transmitted directly to the contacts, forcing them open.
This ensures that the switch contacts will open whenever the switch is activated. NFPA
79 section 13.2, Emergency Stop Devices, specifies the following additional switch
("stop control") requirements:
• Emergency Stop push buttons shall be located at each operator control station and
at other operating stations where emergency shutdown shall be required.
• Stop and Emergency Stop push buttons shall be continuously operable from all
control and operating stations where located.
• Actuators of Emergency Stop devices shall be colored RED. The background
immediately around the device actuator shall be colored YELLOW. The actuator of a
push-button-operated device shall be of the palm or mushroom-head type.
• The Emergency Stop actuator shall be a self-latching type.
NOTE: Some applications may have additional requirements. The user must refer to all
relevant regulations.
If the Module is configured for 1-channel E-stop (S11-S12), a jumper must be installed
on the second channel (S21-S22) and configured for 1-channel input; see Figure 6.
When a 1-channel E-stop is used, the user must guard against failure modes that can
result in an unsafe condition, for example the failure of the contact to a short circuit
condition. A switch with positive opening operation should be used to reduce the
possibility of a failure of the switch to open. A short circuit failure results in loss of
switching function. This can occur from a short across the switch contacts, a short
across the wires connected to the switch somewhere between the switch and the
E-Stop Safety Module, or a short to a secondary source of power. To reduce these
possibilities, physically separate the wires from each other and from other sources of
power (e.g., in separate wireways or conduit).
According to the definition of European standard ISO 13849-1 (EN954-1), a 1-channel
E-stop generally should be used only in an application where Safety Category 2 or less
(1 or B) has been determined via a risk-assessment procedure.
Two-channel E-stops, with positive open switches, are designed to issue a stop
command even in the event of a single failure of this type and provide a high level of
safety.
If the Module is configured for 2-channel E-stop, the immediate normally open output
contacts (13-14, 23-24, 33-34 and 43-44), will open and the normally closed auxiliary
contact (91-92) will close as soon as at least one of the two E-stop contacts opens.
The second contact, however, must open within 2 seconds of the first one; if not, the
unit will go into a lockout condition that results in the outputs opening and requiring a
reset after the fault has been corrected.
Models ES-TN-14H5/-14H6