Parameterization Via Direct I/O Accesses (Only Simatic S5) - Siemens SIMATIC CM35 Manual

Data Communication with the CM35
4.2.2

Parameterization via Direct I/O Accesses (Only SIMATIC S5)

Assignment of the
I/O address area
Use of the consis-
tency bit
Transmission of
parameter blocks
4-8
Parameterization via direct accesses is only permitted in the ²period duration
measurement² and ²timer² operating modes.
The analog I/O address area contains 8 words. The data must be written with
word accesses.
The I/O address area is used for parameterization as shown below.
Table 4-4 Assignment of the address area for parameterization via direct I/O
accesses
Offset for the
Module Start Address
+0
+2
+4 to +14
The consistency ("C bit") in the control word is used with direct- - access para-
meterization to ensure consistency of the written values within one parameter
block.
The CM35 does not evaluate the transferred values of one parameter block as
long as the C bit is not set. These values do not become valid until the con-
trol word is written with C bit = 1.
The following sequence must be used to transfer the pafameter blocks.
1. Transfer the control word with C bit = 0.
2. Transfer all required data of the parameter block.
3. Transfer the control word with C bit = 1.
Transfer next parameter block.
Note
The channels may not be started or stopped by accesses to the control word
while parameter blocks are being transferred. The system must be in a de-
fined state before parameter blocks are transferred.
An example is shown below.
- - ²Timer² operating mode
- - Transmission of the 1st parameter block from DB 20
- - The CM35 has the module start address 128.
Description
DO byte (digital output control)
may not be written during parameterization.
Control word
Parameterization data
(4) J31069-D0416-U001-A5-7618
CM35 Counter Module