ABB ETL600 User Manual

ABB Switzerland Ltd 1KHW001489-EN ETL600
Signal evaluation time Tev1: 4.125 ms
Tev2: 8.25 ms
Tev3: 16.5 ms
The nominal transmission times for the three applications are:
• Blocking T0 = 10 ms
• Permissive Tripping T0 = 11 ms
• Direct Tripping T0 = 12 ms
3.6.6.2.2. Maximum actual transmission time (Tac)
The user can choose one of three programmable applications for each
command. This determines the level of security for the evaluation of
the related tripping signals. Severe disturbances (noise or
interferences) on the transmission path may occasionally introduce an
additional delay of a few milliseconds compared to the nominal
transmission time T0. This delay is generally higher at the same
signal-to-noise ratio (SNR) for commands with higher security
requirements.
The maximum actual transmission time Tac is the maximum
transmission time encountered under noisy channel conditions for a
defined dependability and SNR. It is measured with continuous white
noise applied to the RF input of the ETL600 receiver.
Commands which are not received within a certain Tac are considered
as lost or missed commands (refer also to section 3.6.6.4
'Dependability').
The actual transmission time of the NSD600 is measured, for example,
by means of the manual or cyclic loop tests, refer to section 3.6.8.13
and 3.6.8.14.
3.6.6.3. Security
The NSD600 with its dynamic adaptation of the receiver provides the
best security / dependability trade-off for the chosen command
application at lowest possible transmission time.
Security is expressed as the "worst case" false signal rate (probability
of unwanted commands P
uc
) for blocks of noise of 200 ms duration.
"Worst case" is defined as the level of interference at which the guard
signal is completely suppressed.
The security level P
uc
is fixed for each of the possible command
applications.
The internal security settings for tripping signal evaluation are:
Blocking Puc < 1E-04
Permissive Tripping Puc < 1E-06
Direct Tripping Puc < 1E-09
Security Measurements
3-68 November 2005 Structure and Function

ABB ETL600 Specifications

General

Brand	ABB
Model	ETL600
Category	Touch terminals
Language	English