D8 Series User’s Guide
Chapter 3: Communicating by DeviceNet
46
Bit-Wise Values
Some settings, such as those that enable alarms, are stored as bits within words. To examine the
value of just one bit, you can “and” the value with a mask word to extract the particular bit in which
you are interested. In order to set a bit, perform bit-wise ORing. To clear the bit perform a bit-wise
ANDing with the inverse mask word.
Decimal Placement for Numeric Values
Numeric values that are in the loop’s engineering units are stored as integers. The number of
decimal places that are implied when a parameter value is stored in the controller depends upon the
Input type
and
Disp format
parameter values for the loop. See Table 3.1.
Table 3.1
– Implied Decimals by Input Type and Display Format
INPUT TYPE
DISPLAY FORMAT
DECIMAL PLACES
Any thermocouple
-999 to 3000
1
RTD
-999.9 to 3000.0
1
Process
-999 to 3000
1
-9999 to 30000
0
-999.9 to 3000.0
1
-99.99 to 300.00
2
-9.999 to 30.000
3
-0.9999 to 3.0000
4
To determine the integer value to set in the controller, move the decimal to the right the number of
places specified.
For example:
• If a loop has a process input with a display format of -99.99 to 300.00, values are stored with
two decimal places. If you read a value in the set point register of 2500, you should interpret
that value as 25.00.
• If a loop has a thermocouple input and you want to set the
Alarm High SP
parameter to
355 via DeviceNet™, you should set a value of 3550.
Decimal Placement for Percentage Values
Percentage values are stored internally in tenths of a percent, such that 1000 corresponds to
100.0 percent. Divide values by ten when reading, and multiply values by ten before writing.
D8 DeviceNet Overview
The D8 controller is configured as a Group 2 Only Slave device using the Predefined Master/Slave
Connection Set.
The D8’s DeviceNet™ interface includes objects in two main categories, DeviceNet™ Objects
and Application Objects. DeviceNet™ objects handle what is necessary for networking and
communications. Application Objects provide access to the D8 controller’s parameters and data.
