Smw22 To Smw26: Scan Times; Smb28 And Smb29: Analog Adjustment; Smb30 And Smb130: Freeport Control Registers - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

SMW22 to SMW26: Scan Times

As described in Table D-9, SMW22, SMW24, and SMW26 provide scan time information:
minimum scan time, maximum scan time, and last scan time in milliseconds.
Table D-9 Special Memory Words SMW22 to SMW26
SM Word Description (Read Only)
SMW22 Scan time of the last scan cycle in milliseconds
SMW24 Minimum scan time in milliseconds recorded since entering the RUN mode
SMW26 Maximum scan time in milliseconds recorded since entering the RUN mode

SMB28 and SMB29: Analog Adjustment

As described in Table D-10, SMB28 holds the digital value that represents the position of analog
adjustment 0. SMB29 holds the digital value that represents the position of analog adjustment 1.
Table D-10 Special Memory Bytes SMB28 and SMB29
SM Byte Description (Read Only)
SMB28 This byte stores the value entered with analog adjustment 0. This value is updated once per
scan in STOP/RUN.
SMB29 This byte stores the value entered with analog adjustment 1. This value is updated once per
scan in STOP/RUN.

SMB30 and SMB130: Freeport Control Registers

SMB30 controls the Freeport communications for port 0; SMB130 controls the Freeport
communications for port 1. You can read and write to SMB30 and SMB130. As described in
Table D-11, these bytes configure the respective communications ports for Freeport operation and
provide selection of either Freeport or system protocol support.
Table D-11 Special Memory Byte SMB30
Port 0 Port 1
Format of Format of
SMB30 SMB130
SM30.0 and SM130.0 and
SM30.1 SM130.1
SM30.2 to SM130.2 to
SM30.4 SM130.4
SM30.5 SM130.5
SM30.6 and SM130.6 and
SM30.7 SM130.7
486
Description
Freeport mode control byte
MSB
7
p p d b b b
mm: Protocol selection 00 =Point-to-Point Interface protocol
(PPI/slave mode)
01 =Freeport protocol
10 =PPI/master mode
11 =Reserved (defaults to PPI/slave mode)
Note: When you select code mm = 10 (PPI master), the S7-200 will become a
master on the network and allow the NETR and NETW instructions to be
executed. Bits 2 through 7 are ignored in PPI modes.
bbb: Freeport Baud rate 000 =38,400 baud
001 =19,200 baud
010 =9,600 baud
011 =4,800 baud
d: Data bits per character 0 =8 bits per character
1 =7 bits per character
pp: Parity select 00 =no parity
01 =even parity
LSB
0
m m
100 =2,400 baud
101 =1,200 baud
110 =115,200 baud
111 =57,600 baud
10 =no parity
11 =odd parity