Moore Industries NET Concentrator System AOM, Руководство пользователя

Страница: 100 / 103

NET Concentrator System
®
NCS
- 100 -
Moore Industries-International, Inc.
www.miinet.com
Scaled Integers
To support MODBUS Masters which prefer reading
and processing variables as integers, each PV is also
accessible as a 16 bit integer. For input modules,
the NCS Interface Module will convert the floating
point input value to an integer. This value can then
be read and used by the MODBUS Master. For
output modules, the MODBUS master will generate
the scaled integer, and write it to the NCS Interface
Module. The NCS will convert this value to floating
point, and will use it to drive the output.
Default Integer Scaling Behavior
Default behavior is to scale the PV value between
the channel’s Input/Output Range (or Scaled Range
if Scaling is enabled in a channel) and the Integer
Range of 4096 (0x1000) to 61440 (0xF000) as per
MODBUS Support Table 1. If a DCS does not support
this integer range (for example if they are limited to
integers between 0 and 9999), then “User Defined
Integer Scaling” should be used.
User Defined Integer Scaling
NCS Interface Modules provide for User Defined
Integer Scaling. This allows the user to perform
a system wide override of the values used in the
conversion to and from Scaled Integer values. The
purpose of this is to accommodate MODBUS Register
formats required by existing DCS and PLCs.
On the Configuration page of the NCS Configuration
Software, check the “User Defined Integer Scaling”
check box. This activates the “User Defined Integer
Scaling” and deactivates the “Default Integer Scaling”.
Then enter the Zero, Full and Limits to be used in the
calculation.
MODBUS Support Table 1.
Integer values used in the data
conversion and their default values (prior to Firmware Version 3.12)
MODBUS Support Table 3.
TIM ambient variables (fixed).
MODBUS Support Table 2.
Settings used for the Float Zero and
Float Full values.
Value Name Default Value
Scaled Integer Zero 4096 (0x1000)
Scaled Integer Full 61440 (0xF000)
Scaled Integer Zero Limit 0 (0x0000)
Scaled Integer Full Limit 65535 (0xFFFF)
Data Conversion
Integer data is unsigned. The Float Zero (input/output
lower range) value is mapped to Scaled Integer Zero,
and the Float Full (input / output upper range value) is
mapped to Scaled Integer Full. This range allows an
integer representation of the entire range with some
additional room for out-of-range values. For process
variables the Float Zero and Float Full values are
taken from the Lower Range Value and the Upper
Range Value unless scaling is enabled. If scaling is
enabled, they are taken from the Lower and Upper
Scaled Values. As the variable goes out of range, it is
limited by the Scaled Integer Zero or Full Limit.
Value
Name
Zero Float Input Zero Output Zero Scaling Zero
Float Full Input Full Output Full Scaling Full
Input Module,
Scaling
Disabled Output Module,
Scaling
Disabled Input or Output
Module, Scaling
Enabled
Value Name
Value
Float Zero -40°C
Float Full 85°C
For ambient temperature variables in the TIM, the
ambient operating range is used for the Float Zero and
Full. Thus Float Zero is -40°C, and Float Full is 85°C.
The Float Zero and Float Full values are fixed and
therefore they cannot be sub-ranged per Table A-10.