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Function description
4.3
Safety functions
Safety functions maintain a safe condition on a plant or prevent hazardous conditions
arising on a plant.
The safety functions for electrical drives are defined in EN 61800-5-2.
The safety card implements the following safety functions:
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Safe stop 1 (SS1)
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Safe stop 2 (SS2)
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Safe operating stop (SOS)
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Safe speed range (SSR)
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Safely limited speed (SLS)
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Safe direction (SDI)
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Safely Limited Increment (SLI)
Activation of safety functions
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The safety functions are activated using the single-pole safe inputs on the safety card.
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These inputs operate in accordance with the failsafe principle (on switching off). The
safety control system activates the safety functions via a 1/0 pulse edge.
Feedback from the safety functions
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Message via single-pole semiconductor outputs
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Simultaneous activation of safety functions
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All safety functions can be active at the same time. However, safety function SS1 has
priority over all other safety functions.
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If SS1 is activated, the drive is stopped in accordance with its configuration.
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No other safety functions are processed or called up during this time.
Reaction to limit value violations and errors
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When set limit values are exceeded, the E-STOP braking ramp is activated.
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The safety function STO is activated if there are any internal errors on the safety card
or servo amplifier. The power element is switched off.
4.3.1
Safe torque off - STO
The safety function "Safe Torque Off" (STO) removes the power to the motor. It is imple-
mented via the servo amplifier's shutdown path and the safety card's safe outputs.
Features of the safety function:
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The motor becomes torque-free and no longer generates any hazardous movements.
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To prevent the drive running down in an uncontrolled manner, in normal operation the
safety function STO is activated via the safety function SS1.
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STO is only activated directly when
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Operating Manual PMCprotego S2-2(-C)
1002529-EN-04
"1" signal: Inside the set limit values
"0" signal: Outside the set limit values
there is an internal error on the servo amplifier or safety card
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