DOC-0017-03-EN: AC15 Series - Hardware Installation Manual
DOC-0017-03-EN-B 04.04.2023
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SS1 / STO Implementation using a Safety Control Unit (Stop Category 1):
The example below shows Safe Stop (SS1) implementation that brings a motor to rest in a controlled
manner, before invoking STO on the drive after a time delay determined by an external Safety Control Unit.
The Safety Control Unit shown in this example is a Sick UE410-MU module. This configuration conforms to
SS1 as defined in EN 61800-5-2:2017 para 4.2.3.3 c). Other products are available on the market that may
better suit user’s application, so the user must select and assess appropriate equipment:
Configuration Setup:
TH1
Motor Thermistor ‘+’ connection
TH2
Motor Thermistor ‘-’ connection
DX1
Run Forward:
24V digital input
DI4
Stop:
24V digital input
STOA
24V input connected via ‘
Safety Control Unit
’ DODE o/p signal
STOB
24V input connected via ‘
Safety Control Unit
’ DODE o/p signal
Note: The maximum input level of STOA & STOB inputs is 25.2V. This must be taken into
consideration when selecting a 24V power supply to generate VCC, i.e. VCC(max) < 25.2V.
On system power-up:
1. The Safety Control Unit outputs are de-energised (open-circuit), so STO on the drive is invoked
(active).
To run the drive:
1. Ensure that the ‘Safety Demand’ is reset, i.e., contacts are closed.
2. Close the ‘Start PB’ switch to ensure the Safety Control Unit is reset. This should enable outputs
Q3 & Q4, applying 24V onto STOA & STOB inputs, and hence disabling the STO function.
+24V
SICK UE410-MU
Q3
Q4
A1
A2
X1
X2
I2
I1
Q1
Q2
EN
S1
S3
S2
Fuse = 1A
Drive Start
PB
Drive Stop
PB
Start PB
Safety Demand
(i.e., E-Stop PB)
Time Delayed
Contacts
(DODE)
VCC