Equivalent T-Network - Captron safeCAP SC4 Original Operating Instructions

Performance level e must be achieved.
d = 250 d
op
h = 24 h
op
t = 10 s
cycle
n [cycles / year]
op
n = (d * h *3600 s) / t
op op op
n = 250 d / y * 24 h / d * 3600 s / h / 10 s / cycle = 2,160,000 cycles / year
op
According to the operating instructions, the relay has a lifetime of approximately
20 million cycles before a dangerous failure can occur.
T = 20,000,000 / n
M
T = 20,000,000 / 2,160,000 = 9.3 years
M
According to this calculation, the relay has to be replaced after 9.3 years.
For other relays, values such as B
not considered here and can be requested from CAPTRON.
2.8

Equivalent T-network

If an equivalent T-network is used for the relay, the entire FIT value for the
equivalent T-network must be determined via an FMEDA or an equivalent
method.
The equivalent T-network must not exceed a FIT value of 45, and the MTTF
should be more than 45 years to meet the following formula:
MTTF (Equivalent t-network) = MTTF
d
30).
Exception: MTTF
d
safeCAP SC4
safeCAP SC4 with
MCR-225
cycle
op
10D
(safeCAP) = 100;
or T can be specified. These values are
10D
(safeCAP) * 30 / ( MTTF
d
1.3
d
(safeCAP) -
d
7/19