Rockwell Automation Publication 450L-UM001F-EN-P - March 2022
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Chapter 4 Safety Function
External Device Monitoring
(EDM)
External device monitoring is configurable for both GuardShield product
lines.
EDM is an input signal to the GuardShield receiver. It is used to monitor the
state of the primary control contactors of the guarded machinery or other final
switching devices (FSD). The EDM input is looking for a change of state of the
contactors/FSD within a time period of 300 ms before the system faults. A fault
causes the safety light curtain to enter a lockout condition (OSSDs OFF and
error indication). One reason to select the EDM function can be the detection
of an unsafe condition such as welded contacts in one of the FSD. Activation of
this mode of operation is through the DIP switch setting on the GuardShield
receiver plug-in or by enabling this function in the General settings in
Connected Components Workbench™ software.
EDM is not available in GuardShield safety light curtains with ArmorBlock
Guard I/O connectivity (M12 5-pin QD plug-in).
Low Operating Range
Low operating range is designed to minimize the influence of neighboring
optical sensors on the 450L safety light curtain performance. This feature is
available on all 450L GuardShield safety light curtains. Low operating range
narrows the operating distance. The maximum operating distance is reduced,
and the minimum operating distance is increased.
Low operating range is configured by enabling the appropriate DIP switch on
the receiver plug-in, or by enabling the function in the General settings in
Connected Components Workbench software. The default setting is disabled.
The regional intensity status indicators on the transmitter and receiver
indicate the activation of the low range function.
Beam Coding
Beam coding is only configurable for 450L-E and 450L PAC safety light
curtains.
If several safety light curtains are operating close to one another, it is possible
that one 450L-E/450L PAC safety light curtain system can see the transmitter
infrared light from another 450L-E/450L PAC safety light curtain receiver.
Such a situation is called optical cross talk (see
GuardShield Safety Light Curtains on page 72
) and can cause an unsafe
installation. To reduce the probability of optical cross talk, the 450L-E/
450L PAC safety light curtain is able to exchange the addresses of the sticks
that are paired, and to generate a different transmitter pulse pattern. This
process is referred to as beam coding.
Two settings are available in the 450L-E and 450L PAC safety light curtain —
non-coded and coded. The factory default is non-coded.
If beam coding is selected, you must perform a teach-in procedure once at the
transmitter and the corresponding receiver for pairing the two sticks.
The pairing procedure for systems out of the box is only required at the Rx and
at the Tx transceiver stick when the beam coding function is selected. It must
be done only once after the first power-up.
Set beam coding with the appropriate DIP switch on the plug-in of the receiver
(Rx) stick and power the system up. A confirmation of the configuration can be
required first at the receiver (Rx), if the Rx stick was operated before. In this
case, perform first the configuration confirmation at the Rx and then the
confirmation for the pairing.
