Section 1 Product Description - Banner ES-TA-3F1 Operating Instructions Manual

Key to Categories
• A Functional Stop Category (0, 1 or 2),
per EN60204-1 and NFPA79, refers to the
type of stopping action required by the
guarded machine in question. Some
machines may be stopped safely,
immediately following a stop command
(removal of power); others, due to their
high speed, mass or momentum, would
run on following an immediate stop
command. These machines require power
to be provided to the guarded machine's
braking system for a specified delay time,
to effect a controlled stop.
Category 0 Stop: immediate removal of
power, uncontrolled stop
Category 1 Stop: controlled stop with a
delay before power is removed from
guarded machine
Category 2 Stop: controlled stop with
power left available to the guarded machine
actuators
• A Safety Category (B, 1, 2, 3 or 4), per
EN954-1, refers to "the performance of a
safety related part of a control system (or
circuit) with respect to the occurrence of
faults..." Of the many factors involved when
selecting an appropriate safety category,
hazard analysis, risk assessment and risk
reduction are among the most important.
The level of risk is based on the severity of
a potential harm and its probability of
occurring, which is used to determine the
appropriate performance of a control
system or circuit. Typically, as described in
Annex B of EN954-1, in cases where
serious injury is possible:
- Safety Category 2 would be selected
only if exposure to a hazard is
infrequent, and of a short duration.
- Safety Category 4 would be selected
if exposure to a hazard is frequent to
continuous, or if exposure is for a long
duration.
For more information, refer to standards
EN954-1, EN418, NFPA 79, EN60204-1 and
British Standard 5304:(1988).
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E-Stop Safety Module –
SECTION 1 – Product Description
The purpose of the model ES-TA-3F1 Emergency Stop (E-stop) Safety Module is to
increase the control reliability of a multiple-input Emergency Stop circuit. The ANSI
B11.19 standard states:
"Control reliability of electrical, electronic, or pneumatic systems
frequently consists of multiple, independent parallel or series
circuitry or components so arranged that any single failure . . .
either sends a stop command to the machine tool or prevents a
successive cycle from being initiated."
As indicated in Figure 3, a typical Emergency Stop switch offers two redundant
switching contacts. In a properly designed machine stop circuit, the opening of either of
the two Emergency Stop contacts immediately removes electrical power from the
machine control elements which react to stop hazardous machine motion and/or any
other machine hazard. This redundancy of stopping control offered by a two-pole
Emergency Stop switch is the first step towards control reliability. However, failure or
defeat of one of the switch contacts to a short-circuit will go undetected, thereby
removing the redundancy, and leaving the Emergency Stop circuit prone to eventual
failure.
The model ES-TA-3F1 E-Stop Safety Module connects up to ten Emergency Stop
switches to the machine Emergency Stop control elements. The Emergency Stop
switches become the inputs to the Safety Module, which monitors the condition of both
contacts of each E-stop switch connected to it. The output of the E-stop Safety Module
consists of two redundant output switching channels, each of which is the series
connection of two force-guided relay contacts (K1 and K2 in Figure 3).
As recommended by the Control Reliability section of ANSI B11.19, outputs of the
E-Stop Safety Module consist of two contacts (K1 and K2). These contacts are
mechanically linked, force-guided contacts, allowing the Safety Module to monitor the
outputs for failures. If the Safety Module detects failure of any contact of either the input
E-stop switches or the output relays, the Safety Module output is disabled and cannot
be reset. The two switching output circuits of the Safety Module are rated for up to
250V ac at up to 4 amps (resistive load).
The model ES-TA-3F1 E-Stop Safety Module also provides a selectable (automatic or
manual) reset function.
Model ES-TA-3F1