Banner SC22-3E Safety Controller with Ethernet - Manual (Page 105)

This circuit typically can meet ISO 13849-1 category 2 or category
3 requirements depending on the safety rating and installation of
the mat(s) or other sensor(s). This circuit can detect a short circuit
between channels or to another source of power.
10.6.3 Safety Mat Installation
The mounting surface quality and preparation for the sensor must meet the requirements stated by the sensor’s manufacturer. Irregulari-
ties in the floor (or other mounting surfaces) may impair the function of the sensor and therefore should be reduced to an acceptable
minimum.
The mounting surface should be level and clean. The collection of fluids under or around the sensor should be avoided. The risk of failure
due to build-up of dirt, turning-chips, or other material under the sensor(s) or the associated hardware must be prevented. Special consid-
eration should be given to joints between sensors to ensure that foreign material does not migrate under or into the sensor.
Any damage (e.g., cuts, tears, wear, or punctures) to the outer insulating jacket of the interconnect cable (in the presence of fluids) or to
any part of the exterior of the sensor must be immediately repaired or replaced. Ingress of material (including dirt particles, insects, fluid,
moisture, or turning-chips) which may be present near the mat can cause the sensor to corrode or to lose its sensitivity.
Each sensor must be routinely inspected and tested per the manufacturer’s recommendations. Care must be taken not to exceed opera-
tional specifications (e.g., the maximum number of switching operations).
Each sensor must be securely mounted to prevent inadvertent movement (creeping) or unauthorized removal. Methods include, but are
not limited to, secured edging or trim, tamper-resistant or one-way fasteners, and recessed flooring or mounting surface, in addition to the
size and weight of large mats.
Each sensor must be installed to minimize tripping hazards (particularly towards the machine hazard). A tripping hazard may exist when
the difference in height of an adjacent horizontal surface is 4 mm (1/8") or more. Tripping hazards must be minimized at joints, junctions,
and edges, and when additional coverings are used. Methods include a ground-flush installation of the sensor, or a ramp that does not
exceed 20° from horizontal. Use contrasting colors or markings to identify ramps and edges.
The safety mat system must be sized and positioned so that persons cannot enter the hazardous area without being detected, and can
not reach the hazard before the hazardous conditions have ceased. Additional guards or safeguarding devices may be required to ensure
that exposure to the hazard(s) is not possible by reaching over, under or around the device’s sensing surface.
A safety mat installation must take into account the possibility of easily stepping over the sensing surface and not being detected. ANSI
and international standards require a minimum depth of field of the sensor surface (the smallest distance between the edge of the mat
and hazard) to be from 750 to 1200 mm (30" to 48"), depending on the application and the relevant standard. The possibility of stepping
on machine supports or other physical objects to bypass or climb over the sensor also must be prevented.
Safety Mat Separation (Safety) Distance
As a stand-alone safeguard, the sensor must be installed at a separation (safety)
distance so that the exterior edge of the sensing surface is at or beyond the sepa-
ration (safety) distance, unless solely used to prevent start/restart or solely used
for clearance safeguarding (see ANSI B11.19, ANSI/RIA R15.06, and ISO
13855).
The separation (safety) distance required for an application depends upon sever-
al factors, including the speed of the hand (or individual), the total system stop-
ping time (which includes several response time components), and the depth
penetration factor. The user must refer to the relevant standard to determine the
appropriate distance or means to ensure that individuals can not be exposed to
the hazard(s).
Hazardous
Zone
or
Area
Safety Mat
Ds
K(Ts + Tr) Dpf
Figure 63. Determining safety distance for the
safety mat
SC22-3/-3E Safety Controller Instruction Manual
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