Honeywell HC900 - Manual (Page 50)

42 HC900 Hybrid Controller Communications User Guide Revision 10
12/07
6. Parameters accessible with Function Code 03, 06,10h
6.1 Overview
What’s in this section?
Section 6 describes all parameters accessible by Function Code 03, 06 and 10h. Your particular controller
may not contain all parameters shown. If you see a function that is not on your controller, either it is not
available for that controller model or it is not in your configuration.
How parameters are mapped to addresses
There are two methods available for accessing Modbus parameters:
• Use a fixed map to access pre-defined parameters at fixed addresses. These parameters and their
fixed addresses are described in Sections 6.2 through 6.17.
• Build a custom map to assign parameters to any addresses. These parameters are described in
Sections 6.2 through 6.17. Also, the custom map can contain additional parameters not available
to the fixed map, see Section 6.18. The custom map uses the fixed map’s address assignments as
the default but, unlike the fixed map, you can change these addresses and assign any parameter to
any address. Therefore, the addresses shown for the fixed map don’t necessarily apply to your
custom map. You can see the custom map addresses in HCDesigner, as well as view or print the
custom map.
Your version of HC 900 configuration (pre-4.0 or 4.0 and up) determines the type of address mapping
available, see table below.
Fixed map Custom map
Available in all HC900 configuration versions Available in HC900 configuration version 4.0 and higher.
Certain blocks can be assigned to the custom map that
are not available in the fixed map. (See section 6.18.)
Contains limited types of parameters in limited
quantities (e.g., 32 loops max) More parameters to choose from and unlimited
quantities (e.g., >32 loops)
Function block type (e.g. loop) can be assigned to any
address partitioned for that block type. Can create from scratch or can import fixed map for
customization. Function block type (e.g. loop) can be
assigned to any address or to multiple addresses.
Parameters are partitioned using fixed partitions
according to type (e.g. loops 1-24, SP Programmers 1-
4, etc.) Parameters need not be partitioned or can use custom
partitions
Must use fixed addresses Can use fixed addresses, or can assign parameters to
desired addresses
Can access only the parameters shown in the fixed
map Can access the same parameters as the fixed map but
can use any addresses. Can access additional
parameters not available in fixed map.
Contains gaps in addresses especially between
partitions Address gaps can be eliminated by assigning
parameters to contiguous addresses.