Siemens Simatic S7 Series System Manual

Program instructions
7.2 Clock
S7-200 SMART
166 System Manual, 09/2015, A5E03822230-AC
Format of 8 byte time buffer, beginning at byte address T
You must assign all date and time values in BCD format (for example, 16#12 for the year
2012). The BCD value range of 00 to 99 can assign years, in 2000 to 2099 range.
T byte
Description
Data value
0 Year 00 to 99 (BCD value) Year 20xx: where xx is the two digit BCD value in
T-byte 0
1 Month 01 to 12 (BCD value)
2
Day
01 to 31 (BCD value)
3
Hour
00 to 23 (BCD value)
4
Minute
00 to 59 (BCD value)
5
Second
00 to 59 (BCD value)
6
reserved
Always set to 00
7 Day of week Value ignored when written with the SET_RTC / TODW instruction.
Value reports correct day of week when read with the READ_RTC /
TODR instruction based upon current Year/Month/Day values.
1 to 7, 1 = Sunday, 7 = Saturday (BCD value)
Extended power outage effect on the CPU clock
See the S7-200 SMART system manual appendix A CPU specifications, for how long the
real-time clock can maintain the correct time during power outages.
A CPU initializes with the time values shown in the following table, after an extended power
outage.
Date
Time
Day of week
01-Jan-2000
00:00:00
Saturday
Note
Compact S7-200 SMART CPU models CR40 and CR60 do not have a RTC (Real Time
Clock) or super cap
The READ_RTC and SET_RTC instructions can be used to set the year, date, and time
values in CPU models CR40 and CR60, but the values will be lost on the next CPU power
off
-on cycle. On power-up, the date and time will initialize to January 1, 2000.

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.