Pinnacle Systems STTS - Manual (Page 31)

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ANNEX A
MAT SIZING AND LAYOUT (from #prEN999)
The following formula is an international guideline for proper positioning and applications of safety mats
for machine guarding. This formula must be followed for all safety mat applications supplied to the
European Community (EC) member nations. CEN is the European Committee for Standardization. Final
draft #prEN999.
The minimum distance from the danger zone shall be calculated by using the general formula:
S = (K x T) + C
where:
S Is the safety mat minimum distance in inches/millimeters in a horizontal plane, from the
danger zone to the detecting edge of the safety mat furthest from the danger zone.
K Is a parameter in inches/millimeters per second, derived from data on approach speeds
of the body or parts of the body (K=63 inches/second or 1600mm/second).
T Is the total system stopping time performance (which includes activating the safety mat),
the mat controller output signal switching device, and the time required to stop the
machine and remove risk. T = (Tm +Tc)
Tm Total machine stopping time. Must be obtained by customer.
Tc The STTS safety mat system™ activation time including the controller is 19
msec/mat.
C Is an additional distance in inches/millimeters, based on intrusion towards the danger
zone prior to actuation of the protective safety mat equipment.
(C=48 inches or 1200 mm)
Examples of safety mat sizing calculations using inches and millimeters
S = 63 inches/sec x T + 48 inches
Mat Body approach Total Safety Intrusion distance
Size speed (K) system stopping toward danger zone
time in milliseconds
S = 1600 mm/sec x T + 1200 mm