Instruction Manual

Instruction Manual Supplement
D103639X012
DVC6200 Digital Valve Controller
August 2014
18
Command 35: Write Primary Variable Range Values
In the DVC6200, the Primary Variable is defined to be the Analog Input (loop current).
This command is used to write the ranging values reported in Command 15. It controls how the DVC6200 interprets
the loop current when creating the Travel Target. The upper range must be greater than the lower range.
This command does units conversion, accepting range values in milliamps or percent. If the primary variable is not
configured to use the same units as supplied in this command, the supplied ranges will be converted to PV units before
being applied. Range values are validated against those reported in Command 14 to assure that they are within the
allowable range and are separated by a minimum span.
If the range values are in percent, then they are assumed to be percent of 420 mA. For example, to range an increase
to open unit from 8 mA to 16 mA, but using percent range numbers, specify lower_range = 25% and upper_range =
75%.
This ranging is done in conjunction with the zero power condition. For an IncreasetoOpen valve, the lower range is
the 0% setpoint level (valve plug in the valve seat), while the upper range is the 100% setpoint level. An
IncreasetoClose valve is exactly opposite.
This command will be accepted when the DVC6200’s Instrument Mode is In Service but will be rejected if Write
Protection is in effect.
Byte Format Description Allowable choices
Request
Data Bytes
0 UINT8 Upper and Lower Range Values Unit Code Unit Code 39 (mA) or 57(%)
1  4 Float Primary Variable Upper Range Value
5  8 Float Primary Variable Lower Range Value
Response
Data Bytes
0 UINT8 Upper and Lower Range Values Unit Code Unit Code 39 (mA) or 57(%)
1  4 Float Primary Variable Upper Range Value
5  8 Float Primary Variable Lower Range Value
Code Class Description
Command
Specific
Response
Codes
0 Success No CommandSpecific Errors
2 Error Invalid selection  Units code not 39 (mA) or 57(%)
6 Error Insufficient power
7 Error In Write Protect Mode
9 Error Lower Range too high
10 Error Lower Range too low
11 Error Upper Range too high
12 Error Upper Range too low
13 Error Both ranges are invalid
14 Error Span is too small
16 Error Access Restricted  other master has access locked.
29 Error Upper range less than lower range
32 Error Busy
78 Error NVM Protection Mode