Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manual (Page 23)

IM 12A00A01-61E
3-18 Foundation Fieldbus
3-3-6�-4 Function Block Parameters
Function block parameters can be read from the host or can be set. For a list of the parameters of blocks
held by the EXA, refer to “3-6 List of parameters for each block of the EXA”. The following is a list of impor-
tant parameters with a guide how to set them.
MODE_BLK:
This mode parameter is very important as it gives the state of the block. In O/S (Out_Of_Service) mode the
block is out of operation. In this mode it is allowed to update parameters. Manual mode gives the operator
the possibility to manually update a selected number of parameters (values, scaling e.g.) in order to test the
system. In automatic mode the function block is executed and block parameters are automatically updated.
Under normal operating circumstances, set the Auto mode for normal operation. Auto mode is the factory
default.
Note:
The actual mode is changed by setting the target mode. When the resource block mode is set to
OOS all function blocks in the VFD are set to OOS mode.
CHANNEL:
Transducer blocks convert raw signals into process values. The values are assigned to channels.
For the EXA 202 three or four channels are available.
PH202
1: pH,
2: Temperature,
3: ORP/rH
Channel value unit
1 primary_value primary_value_range.unit
2 secondary_value secondary_value_unit
3 tertiary_value tertiary_value_range.unit
SC202
1: Conductivity/Resistivity,
2: Temperature,
3: Second Conductivity/Resistivity,
4: Concentration
Channel value unit
1 primary_value primary_value_range.units
2 secondary_value secondary_value_unit
3 tertiary_value primary_value_range.units
4 concentration always %
ISC202
1: Conductivity,
2: Temperature,
3: Second Conductivity,
4: Concentration
Channel value unit
1 primary_value primary_value_range.units
2 secondary_value secondary_value_unit
3 tertiary_value primary_value_range.units
4 concentration always %