Overview - Honeywell Touchpoint Plus Safety Manual

1 Overview

IEC 61508 is a generic functional safety standard. Functional safety is defined in IEC 61508 as "part of the overall safety relating
to the equipment under control (EUC) and the EUC control system which depends on the correct functioning of the E/E/PES
(Electrical/Electronic/Programmable Electronic Systems) safety related to systems, other technology safety-related systems,
and external risk re-duction facilities.
The basic operation principle and product descriptions are explained in the user manual of Touch-point Plus. Please refer to
Honeywell Analytics website:
manual (part number: 3011M5001) is avail-able.
Touchpoint Plus has various outputs but only below two output signals are under SIL2 scope:
• Relay output
• 4-20 mA current output
Touchpoint Plus is SIL2 approved by SGS TUV SAAR (Certificate number: FS/71/220/17/0178) with the following safety
parameters in accordance with the combination of input board type (mA input, mV input and Dual input) and output function
(4-20 mA and Relay), Touchpoint Plus's detail PDF and PFH can be summarized as followings:
1) Touchpoint Basic Unit
Input
mA Input
mV Input
Dual Input
2) Touchpoint Expansion Unit
Input
mA Input
mV Input
Dual Input
where,
SFF: Safe Failure Fraction. A percentage of safe failures as compared to all failures
PFD : Average probability of failure to perform its design function on demand (1-year normalized value)
avg
PFH: Probability of a dangerous failure per hour
http://www.honeywellanalytics.com/en-gb/products/Touchpoint-Plus
Safety Function
4-20 mA
Relay
4-20 mA
Relay
4-20 mA
Relay
Safety Function
4-20 mA
Relay
4-20 mA
Relay
4-20 mA
Relay
SFF PDF
> 90% 5.73 X 10
> 90% 5.73 X 10
> 90% 9.48 X 10
> 90% 9.48 X 10
> 90% 7.98 X 10
> 90% 7.98 X 10
SFF PDF
> 90% 6.02 X 10
> 90% 6.01 X 10
> 90% 9.77 X 10
> 90% 9.76 X 10
> 90% 8.27 X 10
> 90% 8.26 X 10
1 Overview
where Touchpoint Plus user
PFH
avg
1.22 X 10
-4
1.21 X 10
-4
2.03 X 10
-4
2.03 X 10
-4
1.70 X 10
-4
1.69 X 10
-4
PFH
avg
1.27 X 10
-4
1.26 X 10
-4
2.08 X 10
-4
2.07 X 10
-4
1.74 X 10
-4
1.73 X 10
-4
Touchpoint Plus Safety Manual
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