2
Installation and wiring
2-29
12. Safety circuit construction example
This section describes category-specific safety circuit configuration examples using a Handy Terminal which
has an ENABLE switch.
Customers should install the appropriate safety measures for their system by referring to the safety circuits
shown in circuit configuration examples, in order to use single-axis robots more safely.
12.1 Performance level
To comply with the machinery directives, the "performance level (PL)" required of the safety circuit must be
evaluated.
Performance levels (PL) are determined by the following parameters:
Major factors that determine performance levels
n
1. Category
2. MTTFd (Mean Time To Dangerous Failure)
3. DCavg (Average Diagnostic Coverage)
4. CCF (Common Cause Failure) : Checklist score > 65 ?
(Please obtain the data on each component from the component manufacturer.)
The performance level (PL) of a safety circuit is determined by the following flow.
Flow for determining performance levels
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1. Determine the "performance level (PLr) required of the safety circuit" by means of risk assessment.
2. Configure the safety circuit that satisfies the requirements of the category that meets PLr.
3. Calculate the safety circuit's "performance level (PL)" from the MTTFd, DCavg, and CCF of the devices used for the
safety circuit, and then make sure that the calculated PL is equal to or higher than the "performance level (PLr)
required of the safety circuit" (PLr
≤
PL).
In the customer's final system, the performance level (PLr) required of the safety circuit should be
determined by means of risk assessment, and then the safety circuit with the corresponding performance
level (PL) should be configured.
Safety parts subject to performance level calculation
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The table below shows the safety parts and B10d reference values.
c
CAutIoN
please obtain the latest information from the parts manufacturers.
Parts Name
Model Name
Manufacturer
B10d
HT1
Emergency stop button
HA1E-V2S2R-TK2354
IDEC
1×10
5
HT1-D
Emergency stop button
HA1E-V2S2R-TK2354
IDEC
1×10
5
Enable switch
A4E-B200HS
OMRON
1×10
5
