36
Setting restriction of HMI (SRH)
Chapter 3
Common functions
3
Setting restriction of HMI (SRH)
3.1
Application
Use the setting restriction function to prevent unauthorized setting changes and to control when
setting changes are allowed. Unpermitted or uncoordinated changes by unauthorized personnel
may influence the security of people and cause severe damage to primary and secondary power
circuits.
By adding a key switch connected to a binary input a simple setting change control circuit can
be built simply allowing only authorized keyholders to make setting changes from the local
HMI.
3.2
Functionality
The restriction of setting via the local HMI can be activated from the local HMI only. Activating
the local HMI setting restriction prevent unauthorized changes of the terminal settings or con-
figuration.
The HMI-BLOCKSET functional input can be configured only to one of the available binary
inputs of the terminal. The terminal is delivered with the default configuration HMI--BLOCK-
SET connected to NONE-NOSIGNAL. The configuration can be made from the local HMI
only, see the Installation and comissioning manual.
The function permits remote changes of settings and reconfiguration through the serial commu-
nication ports. The restriction of setting from remote can be activated from the local HMI only.
Refer to section 2.4.3 "Setting parameters"
for SPA communication parameters.
All other functions of the local human-machine communication remain intact. This means that
an operator can read disturbance reports, setting values, the configuration of different logic cir-
cuits and other available information.
Note!
The HMI--BLOCKSET functional input must be configured to the selected binary input before
setting the setting restriction function in operation. Carefully read the instructions.
Summary of Contents for REL 551-C1*2.5
Page 1: ...Technical reference manual ProtectIT Line differential protection terminal REL 551 C1 2 5 ...
Page 23: ...14 Introduction to the technical reference manual Chapter 1 Introduction ...
Page 39: ...30 Technical data Chapter 2 General ...
Page 63: ...54 Blocking of signals during test BST Chapter 3 Common functions ...
Page 71: ...62 Line differential protection phase segregated DIFL Chapter 4 Line differential protection ...
Page 89: ...80 Thermal phase overload protection THOL Chapter 5 Current ...
Page 101: ...92 Event function EV Chapter 7 Logic ...
Page 163: ...154 Terminal diagrams Chapter 11 Diagrams Figure 39 REL 551 C1 with DC switch ...
