4.4.9
External device monitoring (EDM)
Overview
The external switching elements (external device monitoring, EDM) must be inspected
in line with the regulations which apply at the place of installation or the required
reliability of the safety function.
External device monitoring (EDM) monitors the status of downstream contactors.
Prerequisites
•
Positively guided contactors are used for shutting down the machine.
Functionality
If you configure external device monitoring, then the safety laser scanner checks the
contactors before each time an OSSD pair is switched on. External device monitoring
is then able to detect if one of the contactor’s contacts is welded, for instance. In this
case, the OSSDs remain in the OFF state.
24 V DC
k2
k1
K1
0 V DC
OSSD A
EDM
OSSD B
K2
Figure 47: Electrical diagram of external device monitoring (EDM)
When the contactors (K1, K2) reach their rest position after the protective device has
tripped, the two N/C contacts (k1, k2) close in a positively guided manner. 24 V is
then present at the input of external device monitoring. If 24 V is not present before
the OSSD pair is switched on, then one of the contactors is faulty and external device
monitoring is preventing the OSSD pair from switching to the ON state.
In addition, external device monitoring checks the contactors after the OSSD pair
is switched on. If both N/C contacts (k1, k2) remain closed after the OSSD pair is
switched on, the OSSD pair switches back to the OFF state.
Complementary information
Each OSSD pair in the safety laser scanner is equipped with a configurable internal
EDM.
4.5
Integration into the network
4.5.1
Network services and ports
Table 5: Network services and ports
Use
Protocol
Source
Source port
Target
Destination port
SNMP
UDP
SNMP client
Selected by SNMP
client
microScan3
161
microScan3
161
SNMP client
Selected by SNMP
client
DHCP
UDP
microScan3
68
DHCP server
67
DHCP server
67
microScan3
68
SNTP
UDP
microScan3
123
NTP server
123
NTP server
123
microScan3
123
PROJECT PLANNING
4
8025424/1ELL/2022-01-21 | SICK
O P E R A T I N G I N S T R U C T I O N S | microScan3 Pro I/O
73
Subject to change without notice
