Wiring The Interval Counter Input - Siemens SIMATIC SM 335 Manual

4.3

Wiring the interval counter input

Principle
Figure 4-2 shows how to connect the interval counter input with a switch. The
switch is actuated by a cam. The cam is on a rotating shaft, such as the barrel ex-
truder of an injection molding machine.
Cam
Fig. 4-2
Voltage supply
A 24 V voltage is required for the interval counter input. Utilization of the load volt-
age (24 V) is recommended.
Current
In the '1' state (+ 24 V present), a current of no less than 2.5 mA and no more than
4.4 mA must flow through the signal line.
The minimum current must be observed, for example, when an electronic switch
(such as an initiator) with a certain voltage drop is used in place of the mechanical,
low-bounce switch shown in Figure 4-2. The maximum current must be observed if
you wish to use a voltage higher than 24 V to compensate for the voltage drop.
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
+24 V
Low-bounce switch
I
M
Connecting a Sensor to the Interval Counter Input
Interval Counter Input
L
+
IZ
M
IZ
4-5