Fieldbus Valve Coupler FD0-VC-Ex4.FF
Parameterisation and operation of the valve coupler
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Subject to reasonable modifications due to technical advances.
Copyright Fuchs, Printed in Germany
Fuchs Group • Tel.: G49 621 776-0 • USA +1 330 4253555 • Sin65 67799091 • Internet http://www.pepperl-fuchs.com
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The DI function block complies with the Foundation Fieldbus specification. Using the DI function block, all
8 PFC sensor values can be read at the same time and be processed in a function block application.
6.2
Identification, device ID
Each F
OUNDATION
fieldbus device has an unequivocal device ID. This device ID is structured as follows for
the valve coupler FD0-VC-Ex4.FF:
The manufacturer identification "502B46" is for the Fuchs GmbH, the type "0001" identifies the
valve coupler. These three fields are the same for all valve couplers FD0-VC-Ex4.FF.
A differentiation can be made via the serial number if several valve couplers are connected to one FF-H1
segment. The serial number is provided on a label at the right side of the device.
6.3
Interaction of the transducer blocks and the DO function blocks
In each of the DO function blocks, a reference value is calculated for the valve position in the parameter
OUT_D which is transferred to the transducer block which is connected with the function block. The con-
nection between a function block and a transducer block is made via the parameter "Channel" of the func-
tion block. The channel number (1 ... 4) of the transducer block is entered in this parameter with which the
function block shall interact.
OUT_D of the function block can assume values from 0 to 255. The value "0" means valve "closed", values
unequal to zero mean valve "open". Such a specified reference value is contrary to many conventional de-
vices where the number "0" means "valve current OFF" and "1" means "valve current ON". The reference
value is taken over by the transducer block only if the status is "good (C)“ or "Good (NC)“. However, if the
status is "uncertain" or "bad", the auxiliary valve is not controlled electrically and the drive moves into the
mechanical safety position.
If the current position of the valve is determined via two PFCs, the transducer block transfers the current
position back to the DO function block. The function block represents the transferred value in the parameter
READBACK_D. The numerical value depends on the parameterisation of the transducer block (see section
6.5.4).
This relation is illustrated by figure 6.2.
Manufacturer Type
Serial number
502B46
0001
021400564026
In addition to the reference value for the valve position and the current valve position, also diag-
nosis information is transferred between the function block and the transducer block. Thus it is
possible to receive diagnosis messages from the transducer block also with control systems
which do not support alarms of transducer blocks. More detailed information in that connection
can be found in section 6.7
The parameter READBACK_D is shown at the parameter PV_D within the DO function block. If
the IO option "invert" is activated in the function block, the numerical value is inverted. I. e. a
value of "0" becomes "1", a value unequal to zero becomes "0".
If the current valve position shall be transferred in cycles to a control system or used in a func-
tion block application, the value of PV_D can be transferred to BKCAL_OUT_D via the IO option
"PV for BKCal_Out". If this option is not activated the value of BKCAL_OUT_D is only a copy of
the current reference value.
