Siemens simatic s7-400 FM 450-1, User Manual, Page: 46 / 130

Program
6.5 Technical specifications of the blocks
Counter module FM 450-1
46
Manual, 02/2014, A5E03648739-02
6.2 The FC CNT_CTRL function
Functionality
The data required for the FC CNT_CTRL are stored in a DB on the CPU. The
FC CNT_CTRL transfers data cyclically from this DB to the FM and fetches data from the
FM.
Requirement
● You have created a DB under STEP 7 as a data block with assigned user-specific data
type.
For this purpose select the UDT 1 as the source. The UDT 1 was copied into the block
library for the counter (FM_CNT) when the FCs were installed. You must not modify the
UDT 1. Copy the UDT 1 into your project together with the FCs.
● The following valid data must be assigned to the DB required for the FC CNT_CTRL:
–
Module address
Set the module address (basic address of the FM 450-1) when you configure your
hardware.
The module address must be entered in the MOD_ADR parameter in the DB.
To enter the module address, the following methods can be used:
Recommended procedure
Make the assignment of the module address to the DB in the user program so that the
assignment of the module address occurs when user program is called in OB 100 (see
example below).
Alternative procedure
You can have the module address entered automatically when you select the module
in HW Config, open the "Properties" dialog box with the menu command Edit > Object
Properties, and select the DB using the "Mod Addr" button there. However, in this
case, the values entered in the DB (including the module addresses) will be reset to
their initial values when a consistency check (menu command Edit > Check Block
Consistency opens the "Check Block Consistency" dialog box) is performed followed
by compilation (menu command Program > Compile All in the "Check Block
Consistency" dialog box).
If a consistency check is performed without compilation, the values are not changed.
The menu command Edit > Compile All is only required within a consistency check
when the project has been edited with STEP 7 V5.0 Service Pack 2 or earlier.
– Channel address
The channel address of count channel 1 is the same as the module address in pointer
format. The channel address of count channel 2 is the same as the module a
32 in pointer format.
– User data length
The user data length is 32.