Fieldbus Valve Coupler FD0-VC-Ex4.FF
Parameterisation and operation of the valve coupler
36
Subject to reasonable modifications due to technical advances.
Copyright Fuchs, Printed in Germany
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6.5.10
Valve and drive information
Information of the valve drive or transducer block can be entered in the following parameters. The first three
parameters are a component of all F
OUNDATION
fieldbus blocks. Their use depends on the control system.
•
„STRATEGY“
Grouped blocks can be identified by entering a number. This number is not controlled or used by the
block.
•
„ALERT_KEY“
Identification number for the plant unit which is used by the master computer to sort e. g. alarm or oper-
ation messages. Values from 0 to 65535 are valid.
•
„TAG_DESC“
Description of the task of the TB.
•
"Mechanical drive manufacturer"
•
"Mechanical drive model"
•
"Mechanical drive serial number"
•
"Valve manufacturer"
•
"Valve model"
•
"Valve type" - undefined, linear, turning, other
•
"Valve serial number"
6.6
Process information
6.6.1
Valve reference value
The reference value for the valve position and the associated status are shown in the "Final Value" param-
eter (reference value). The "Final Value" is a copy of the OUT_D value of the DO function block connected
with the transducer block. This reference value can assume the values "closed" (0) or "open" (unequal to
0). The value is accepted only with a status "Good NonCascade" or "Good Cascade". If the status is "Bad"
or "Uncertain", the connected auxiliary valve is not controlled electrically so that the associated drive moves
into the mechanical safety position.
6.6.2
Valve position
The signals recorded by a connected final position feedback are indicated in several parameters of different
significance.
"Sensor Value A"
This parameter displays the input signal of PFC A. The valve coupler interprets a PFC signal as follows:
high current
=> logical 1
low current
=> logical 0
"Sensor Value B"
See "Sensor Value A“.
"Valve Position"
The current valve position "open", "intermediate" or "closed" is displayed as value. By parametering of "Sen-
sor usage" (section 6.5.4) the signals of the PFCs is assigned a definite position.
"Extended valve position"
The information in "Valve Position" is extended in the intermediate position by the information "opening" and
"closing". This information is determined from the current control process and need not coincide with the
actual direction of travel (e. g. when changing the set position while the valve is in the intermediate position).
