Siemens CPU 312 IFM User Manual

Cycle and Reaction times
3-7
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
Table 3-2 Process image update of the CPUs
Components CPU
312
IFM
CPU
313
CPU
314
CPU
314
IFM
CPU
315
CPU
315-2
DP
CPU
316-2
DP
CPU
318-2
K Base load 162s 142s 142s 147s 109s 10s 10s 20s
A For each byte in rack
“0”
14.5s 13.3s 13.3s 13.6s 10.6s 20s
(per
word)
20s
(per
word)
6 s
B For each byte in racks
“1 to 3”
16.5s 15.3s 15.3s 15.6s 12.6s 22s
(per
word)
22s
(per
word)
12.4s
D For each byte in DP
area for integrated DP
interface
– – – – – 12s
(per
word)
12s
(per
word)
1s
User Program Processing Time:
The user program processing time is made up of the sum of the execution times
for the instructions and the SFB/SFCs called up. These execution times can be
found in the Instruction List. Additionally, you must multiply the user program
processing time by a CPU-specific factor. This factor is listed in Table 3-3 for the
individual CPUs.
Table 3-3 CPU-specific Factors for the User Program Processing Time
Se-
quence
CPU 312
IFM
CPU 313 CPU 314 CPU 314
IFM
CPU 315
CPU
315-2DP
CPU
316-2 DP
CPU
318-2
Factor 1.23 1.19 1.15 1.15 1.15 1.19 1.19 1.0
S7 timers
In the case of the CPU 318-2, the updating of the S7 timers does not extend the
cycle time.
The S7 Timer is updated every 10 ms.
You can find out in Section 3.3 how to include the S7 timers in calculations of the
cycle and response times.
Table 3-4 Updating the S7 Timers
Sequence
312 IFM 313 314 314 IFM 315
315-2DP
316-2DP
Updating the S7
timers (every 10 ms)
Number of
simultaneously
active S7
timers  10 s
Number of simultaneously active S7 timers  8 ms

Siemens CPU 312 IFM Specifications

General

Brand	Siemens
Model	CPU 312 IFM
Category	Controller
Language	English