Function Block Link Definitions - YOKOGAWA digitalYEWFLO Series User Manual

The node addresses are used to locate devices
for communication purposes. Since a PD tag is too
long a data value, the host substitutes the node
addressed for PD tags in communication. Node
addresses can be set to numbers in a range of
decimal 20 to 247 (hexadecimal 14 to F7). Assign
devices having link master functionality (i.e., LM
devices) from the smallest address number (0x14)
in order, and other devices (i.e., basic devices) from
the largest (0xF7). Assign an address in the range
for basic devices to a digitalYEWFLO. Only when
using a digitalYEWFLO with LM function as an
LM device, assign an address in the range for LM
devices to it. These address ranges are determined
by the following parameters.
Table 5.1 Parameters for Setting Address Range
Symbol Parameters
V (FUN) First-Unpolled-Node Indicates the address next
V (NUN) Number-of-
consecutive-
Unpolled-Node
Any devices within an address range written as
"Unused" in Figure 5.1 cannot join the fieldbus.
Other address ranges are periodically scanned to
find any devices newly joining the fieldbus. Do not
widen the available address ranges unnecessarily;
the fieldbus communication performance may be
severely degraded.
0x00
0x0F
0x10
0x13
0x14
V(FUN)
V(FUN)+V(NUN)
0xF7
0xF8
Default addresses
0xFB
0xFC
Portable device addresses
0xFF
Figure 5.1 Available Range of Node Addresses
Description
to the address range used
for the host or other LM
device.
Unused address range
Unused
Bridge device
LM devices
Unused V(NUN)
Basic devices
F0501.ai
<5. CONFIGURATION>
To ensure stable operation of Fieldbus, determine
the operation parameters and set them to the LM
devices. While the parameters in Table 5.2 are to
be set, the worst-case value of all the devices to
be connected to the same Fieldbus must be used.
Read the specification of each device for details.
Table 5.2 Operation Parameter Values of
digitalYEWFLO to be Set to LM Device
Symbol Parameters
V (ST) Slot-Time
V (MID) Minimum-Inter-
PDU-Delay
V (MRD) Maximum-
Response-Delay
5.3 Function Block Link
Definitions
Link the input/output parameters of function blocks
to each other as necessary. For a digitalYEWFLO,
the output parameters of three AI blocks (OUTs),
those of two DI blocks (OUT_Ds), input/output
parameters of AR block, IT block and optional PID
block (option /LC1) should be linked to parameters
of different function blocks. Specifically, link
settings must be written to the link object in the
digitalYEWFLO. For details, read Section 5.6 "Block
Setting." It is also possible to read values from the
host at appropriate intervals instead of linking the
outputs of digitalYEWFLO's function blocks to other
blocks.
The linked blocks need to be executed
synchronously with other blocks and the
communication schedule. In this case, change
the schedule of the digitalYEWFLO according to
Table 5.3, in which factory settings are shown in
parentheses.
5-2
Description and Settings
Indicates the time
necessary for immediate
reply of the device. Unit of
time is in octets (256 μs).
Set maximum specification
for all devices. For a
digitalYEWFLO, set a value
of 4 or greater.
Minimum value of
communication data
intervals. Unit of time is in
octets (256 μs). Set the
maximum specification
for all devices. For a
digitalYEWFLO, set a value
of 4 or greater.
The worst case time
elapsed until a reply is
recorded. The unit is
Slot-time; set the value so
that V (MRD) x V (ST) is
the maximum value of the
specification for all devices.
For a digitalYEWFLO, value
of V(MRD) x V (ST) must be
12 or greater.
IM 01F06F00-01EN