Safety Integrated - Industry - Siemens

Network 4: Reading in the readback signals
The opening auxiliary contact of contactor K2 is connected
with the digital input module of the S7-400 (K2_HELP). The
readback signal is evaluated in the F-program. C_K2_HELP
makes the readback signal available to the F-CPU.
Network 5-7: Speeds for MASTERDRIVES
NW Task Note/explanation Code
5 Conversion of
actual speed value
in 1/min with
PROFIBUS
6 Converting the
setpoint speed
value for the operating
mode
"safe speed"
(SG):
7 Normal operation
or "safe
speed" (SG)
This network determines the actual speed value read
with PROFIBUS and provides this value to the DP slave for
standstill evaluation.
Maximum speed: 6000 1/min
Maximum value of MASTERDRIVES: 4000hex=16384dec
The ratio of both numbers make up a factor which initially
is stored in a temporary variable #TEMP1. Via the PEW
258 the value representing the actual speed value is
read in by MASTERDRIVES. Multiplication of this value
with #TEMP1 results in the actual speed in 1/min. This
value is transmitted to the F-CPU with C_N_ACT.
The value C_N_SG is provided by the F CPU in 1/min. After
conversion (4000hex correspond to 6000 1/min) this
value is available in MASTERDRIVES as
N_SG_FOR_MDRIVE.
If C_EN_SG=1, the "safe speed" stored in the F-program
is transmitted to MASTERDRIVES (transfer command in
PAW 258). For C_EN_SG=0 the setpoint speed value
stored in DB1 is transferred to MASTERDRIVES for normal
operation.
OB "COMPLETE RESTART" (OB 100)
In OB 100 the values for MASTERDRIVES are default and become
active on starting up the S7-CPU.
Functional Example No. AS-FE-I-012-V10-EN 387
Ex. No.
12