Honeywell 5704 Operating Instructions Manual page 190

MAN0448_Issue 13_ 01-2010
005704-M-5001 A03249
CHAPTER 10 -SPECIAl CONDITIONS FOR SAFE USE ACCORDING
TO EC-TyPE ExAMINATION CERTIFICATE BVS 04 ATEx G 001 x
- When relays are used for signalling update alarms, no
other alarms or messages must be allocated to them.
Configuration of update messages for "inhibit" should be
avoided.
- Time delayed relays shall not be used.
- The status of the control unit obtained via Modbus shall
be used only for the purpose of visualisation or
documentation but not for safety purposes. Write access
via Modbus shall be avoided. This certificate is concerned
solely with information which can be obtained from Modbus
functions 02 and 04.
- When a control card 5701 is configured for master or
voted alarms as well as master or voted fault or inhibit
messages, high integrity relay cards should be used. If
no high integrity relay cards are used, triple relay cards
shall be used. In such cases, both the relays and the
LEDs of this control card will reflect only the status of the
master or voting group. For an "X out of Y" linkage with
vote counts (X) > 1, local alarms or messages of this
control card are not displayed if less than X control cards
have entered the alarm, fault or inhibit status, respectively.
Therefore, voting groups have to be configured in such a
way that vote counts of "1" are used for voted faults and
inhibit messages to allow for signalling of local fault and
inhibit states of the control card.
- Relay 1 of a high integrity relay card is always assigned
to a local fault. It is also used for signalling malfunction of
the high integrity relay card itself. Therefore, this relay
shall be monitored for each high integrity relay card.
- The alarm level with the highest safety relevance shall be
configured as latching.
- The control unit shall be mounted in a vibration-free
environment.
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5704 Control System