System Manual HS3A-H21M4
20
Notes for operation with safe control systems
Important!
Please observe the following requirements for connection to safe control systems:
Use a common power supply for the control system and the connected
safety switches.
A pulsed power supply must not be used for U
B
. Tap the supply voltage
directly from the power supply unit. If the supply voltage is connected to a
terminal of a safe control system, this output must provide sufficient elec-
trical current.
Always connect inputs IA and IB directly to a power supply unit or to outputs
OA and OB of another HS3A device (series connection). Pulsed signals
must not be present at inputs IA and IB.
The safety outputs (OA and OB) can be connected to the safe inputs of a
control system. Prerequisite: The input must be suitable for pulsed safety
signals (OSSD signals, e.g. from light curtains). The control system must
tolerate clock pulses on the input signals. This normally can be set up by
parameter assignment in the control system. Observe notes of the control
system manufacturer. For the pulse duration of your safety switch, please
refer to the section Typical system times on page 25.
