19
P94DVN01A
Explicit Messaging
6
Explicit Messaging
6.1 Objects 64h and 65h
The PositionServo system objects 64h and 65h encapsulate all valid PositionServo variables (Property IDs or
PIDs). Object 64h covers PIDs in range 1-255. Object 65h covers PIDs in range 256 and up. Each PositionServo
PID is represented by an instance of a System940 object. For object 64h the instance number matches the
PID’s index. For object 65h instance calculated as:
Object 65h Instance = PID – 255 , for PIDs with ID 256 and up
6.2 Example Explicit Message
NOTE:
The complete list of variables (PIDs) can be found in the PositionServo Programming Manual
(PM94M01).
Example of how to access PID # 275:
Since PID 275 > 255, it falls under Object 0x65 and the Instance ID is (275 – 255) = 20 (0x14 in hex).
All aspects of control and parameterization in the PositionServo drive are accomplished through the system
variables. Some of the variables are parameters such as Current Limit or Target Position. Some of the variables
are action properties, i.e. writing values to these variables will execute a particular process. As an example,
writing to variable VAR_ENABLE (ID=52), a non-0 value will enable the drive. Writing the same variable with a
0 (zero) value will disable the drive. Another example could be writing the variable VAR_MOVED with a value of
10, which would execute relative motion for 10 user units.
Every variable in the PositionServo can be read/written as a 32-bit INTEGER or 32-bit REAL(float) value.
Conversion is done automatically. In addition each variable can be read from its RAM (current) copy or from
non-volatile (EPM) storage. The value is initialized at the time of power up. To accommodate different access
(RAM or EPM) and format (integer or float) types, attributes are implemented. For example to reach variable
VAR_CURRENTLIMIT (ID=30) as FLOAT in RAM (run-time value) you would use InstanceID = 30 with attribute
2. For the same variable accessed in EPM (non-volatile copy) you would use attribute 3. Refer to Table 13.
Table 13: Objects 64(Hex) and 65(Hex)
Instance Attributes
Integer, RAM
0
Integer, EPM
1
Float, RAM
2
Float, EPM
3
String, RAM
4
String, EPM
5
Instance Services
Get_Attribute_All
Get_Attribute_Single
Instance
Instance = variable ID.
Refer to PositionServo Programming Manual (PM94M01) for variable ID list.
For example: Instance of VAR_CURRENTLIMIT is 30 since its ID=30.
