Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manual (Page 14)

IM 12A00A01-61E
Foundation Fieldbus 3-9 3-9
LI100
LIC100
FIC100 FC100
FI100
Commu-
nication
Schedule
OUT
IN
OUT
CAS_IN
BKCAL_OUT
BKCAL_IN
BKCAL_IN
BKCAL_OUT
IN
Unscheduled
Communication
Scheduled
Communication
Macrocycle (Control Period)
Figure 3.8 Function Block Schedule and Communication Schedule
When the macrocycle is set to more than 4 seconds, set the following intervals to be more than 1% of the
macrocycle.
- Interval between “end of block execution” and “start of sending CD from LAS”
- Interval between “end of block execution” and “start of the next block execution”
“end of block execution” and “start of the next block execution”
3-3-4 Setting of Tags and Addresses Setting of Tags and Addresses
This section describes the steps in the procedure to set PD Tags and node addresses in the EXA.
There are three states of Fieldbus devices as shown in Figure 3.9, and if the state is other than SM_
OPERATIONAL state, no function block is executed. EXA must be transferred back to this state after a tag
or address is changed.
Tag clear Tag setting
Address clear Address setting
UNINITIALIZED
(No tag nor address is set)
INITIALIZED
(Only tag is set)
SM_OPERATIONAL
(Tag and address are retained, and
the function block can be executed.)
Figure 3.9 Status Transition by Setting PD Tag and Node Address
EXA has a PD Tag and node address that are set upon shipment from the factory unless otherwise speci-
fied. To change only the node address, clear the address once and then set a new node address. To set
the PD Tag, first clear the node address and clear the PD Tag, then set the PD Tag and node address
again.
Devices whose node address was cleared will await the default address (randomly chosen from a range
of 248 to 251, or from hexadecimal F8 to FB). It is necessary to confirm the device ID in order to correctly
order to correctly
specify the device. The device ID of the EXA is 594543083xxxxxxxxx. (The xxxxxxxxx at the end of the
above device ID is a total of 9 alphanumeric characters. The characters displyed on the screen when each
instrument is powered on, correspond to the xxxxxxxxx and if necessary, should be recorded.)