Siemens SIMATIC TI555 - Figure 2-6 Contact Noise Snubbing

2-10
Pre-installation Guidelines TI545/TI555 System Manual
Correcting Noise Problems (continued)
You can also use contact snubbing (shown in Figure 2-6) as an alternative
type of snubbing.
Both types of snubbing cause the physical devices to come on or go off more
slowly . The resistance-capacitance (RC) and metal oxide varistor (MOV)
elements should have minimal effect on system timing; their time constants
are substantially less than one millisecond.
Discrete
input Load
CR
Discrete input
module protection
RC snubbing
Discrete
input Load
Discrete input
module protection
MOV snubbing
MOV
Input Power Input Power
Figure 2-6 Contact Noise Snubbing
NOTE: Noise snubbing shown in Figure 2-6 is built into the PPX:505-5518
Relay Output module.