Specifications

Presence Sensing Safety Devices
MatGuard™ Mats
2-92
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Publication S117-CA001A-EN-P
Overview
General 1-Principles
2-Safety Mats 3-Safety Switches 4-Operator
Interface
5-Logic
R
Note: The standard MatGuard mat can be successfully used with
fork lift trucks. The MatGuard Mat System should be installed in
accordance with the requirements of EN 999, “The positioning of
protective equipment in respect of approach speeds of parts of the
human body.”
Application Details
Safety Distance Calculations ANSI/RIA R15.06
The minimum distance calculated is the minimum horizontal
distance from the outer edge of the MatGuard sensor mat detection
zone to the nearest part of the hazard. The formula for floor
mounted safety mats is:
Ds = [K x (Ts + Tc + Tr)] + Dpf
 Ds is the minimum safety distance.
 K is a minimum speed constant based on the movement of the
hand/arm only and the body being stationary.
K=1600 mm/s (63 in./s)
 Ts is the worst stopping time of the machine/equipment.
 Tc is the worst stopping time of the control system.
 Tr is the response time of the safeguarding device.
 Dpf is the depth penetration factor which is the maximum travel
towards the hazard within the safety mat area that may occur
before a stop is signalled.
Dpf=1200 mm (48 in.)
T = Ts + Tc + Tr
0.035 + 0.485
0.520 s
S = (63 x 0.520) + 48
80.76 in.
Sensor mats will be required from 2032 mm right up to the edge of
the machine base plate.
Safety Distance Calculations EN999
The minimum distance calculated is the minimum horizontal
distance from the outer edge of the MatGuard sensor mat detection
zone to the nearest part of the hazard. The formula for floor
mounted safety mats is:
S = [1600 x (t1 + t2)] + (1200 – 0,4H)
 S is the minimum safety distance in mm in a horizontal plane from
the danger zone to the detecting edge of the device furthest from
the danger zone.
 1600 is a minimum speed constant based on the movement of the
hand/arm only and the body being stationary.
1600 mm/s = 63 in./s
 t
1
is the maximum time between the actuation of the sensing
function and the output signal switching devices being in the off
state.
 t
2
is the maximum response time of the machine, i.e., the time
required to stop the machine or remove the risks after receiving
the output signal from the protective equipment.
 1200 is the depth penetration factor which is the maximum travel
towards the hazard within the safety mat area that may occur
before a stop is signalled.
1200 mm = 48 in.
 H is the distance above the reference plane, e.g., floor, in
millimeters.
The MatGuard Safety Mat system is also designed to meet the
U.S. standards ANSI/RIA R15.06-1999 Safety Requirements for
Industrial Robots and Robot Systems and ANSI B11.19
Performance Criteria for Safeguarding.
These two U.S. standards have many similar requirements and
provide performance criteria for design, installation and use.
Excerpts from these standards include:
From RIA R15.06
(From 11.7) Safety mat systems shall be designed, constructed,
and applied such that any single component failure shall not prevent
the stopping action of the robot.
(From 5.3.4) Safety mats shall have a minimum object sensitivity
which detects 30 kg (66 lb,) weight of an 80 mm (3.125 in.) diameter
circular disk anywhere on the mat sensing surface; provide a means
to retain minimum object sensitivity at the area where mats joined
together.
From ANSI B11.19
(From 11.1.1.4) The safety mat device shall have a maximum
response time that is not affected by object sensitivity adjustments
or environmental changes.
(From 11.1.1.5) When a component, module, device or system
failure occurs, the safety related function shall prevent initiation of
the hazardous machine motion, initiate an immediate stop
command and prevent re-initiation of the hazardous machine
motion.
From AS 4024.5
The MatGuard Safety Mat system is designed to meet the Australian
Standard AS 4024.5, which has many similarities to the European
Standard EN1760-1. Excerpts from this standard include:
(From 3.2.2) Where an effective sensing area is built up of more
than one sensor, it shall have no dead zone.
(From 3.7) When the actuating force is applied the output signal
switching device (s) shall change from an 'on' state to an 'off' state.
It shall remain in the 'off' state for at least as long as the actuating
force is applied.
(From 3.8) The sensor shall be provided with a means for fixed
permanent location.
(From 3.10) Provisions shall be made on the top surface of the
sensor to minimize slipping under the expected operating
conditions.
The response time of the machine and control system used in the
calculation must be the worst case. Some machines have
inconsistent response times that are dependent upon mode of
operation, nature of the work piece and point in the operating cycle
at which stopping is initiated. An allowance should be made for
wear in brakes, temperature, aging of components, etc., if this can
affect the response time. An allowance for further delays in the
machine control system may be required in some circumstances.
Calculation Example
In this example, the MatGuard system is being used with a machine
and control system with a worst-case response time measured at
0.485 seconds. The system is on a flat surface, it is not on a raised
platform. Using the formula above.