Siemens SIMATIC S5 Manual page 123

Programming the IP 265 with COM 265
Timer operations (
The timer operations in an IP 265 user program are very similar to those in a CPU user program,
with two exceptions:
• The IP 265 timer operations have no time element numbers.
• Current times for IP 265 timer operations cannot be read out.
The time base for IP 265 timer operations differs from that used in STEP 5 (CPU programming).
•
All IP 265 timer operations have the same structure:
Timer's Start input (S): On a signal state
change, the timer is initialized to its preset
value.
Preset value specifying the initial time
value (TV) for the timer
Reset input (R):
Timer is reset to its initial state.
Figure 9-4. Basic Structure of "Timer" Language Elements
The preset value is defined via a time constant or parameter.
The time constant is defined by specifying a time base (coded) and a time:
KT 40. 2
Key for time base:
Time base
Time factor
Parameters which define times must be written with symbolic identifiers in the IP 265 user program.
The initialization of timers is discussed in detail in Section 9.4.2 of the Product Manual. Parameter
initialization via the CPU user program is covered in Section 6.
9-18
T)
Operand
Coded time base
Time (0 to 999)
No postfix
0.001 s
Identifier for a timer operation:
Example: "1
xxx
>
S
TV
In dependence on the
R Q
timer operation, output Q
shows whether or not the
timer has run down.
.0 .1
0.01 s 0.1 s
IP 265
"
.2
1 s
EWA 4NEB 812 6130-02a