Banner SC22-3E Safety Controller with Ethernet - Manual (Page 40)

CAUTION: . . . Adjustable Valve Monitoring (AVM) Operation
When an input is configured with automatic reset logic and is quickly cycled (from Run to Stop to Run), the Safety Output(s)
will not turn ON until the AVM input is satisfied. This could result in an ON-delay up to the configured AVM monitoring
time.
It is the user's responsibility to ensure the AVM monitoring time is properly configured for the application and to
instruct all individuals associated with the machine about the possibility of the ON-Delay effect, which may not be
readily apparent to the machine operator or to other personnel.
4.7 EDM, OSSD (Safety Output), and FSD Hookup
4.7.1 External Device Monitoring (EDM)
The Controller’s Safety Outputs can control external relays, contactors, or other devices that have a set of normally closed (N.C.) force-
guided (mechanically linked) contacts that can be used for monitoring the state of the machine power contacts. The monitoring contacts
are normally closed (N.C.) when the device is turned OFF. This capability permits the Controller to detect if the devices under load are
responding to the Safety Output, or if the N.O. contacts are possibly welded closed or stuck ON.
The EDM function provides a method to monitor these types of faults and to ensure the functional integrity of a dual-channel system,
including the MPCEs and the FSDs.
An EDM input can be mapped to only one Safety Output.
The EDM inputs can be configured in three ways: one-channel, two-channel, or no monitoring. One- and two-channel EDM are used
when the OSSD outputs directly control the de-energizing of the MPCEs or external devices.
• One-Channel Monitoring: a series connection of closed monitor contacts that are forced-guided (mechanically linked) from each
device controlled by the Controller. The monitor contacts must be closed before the Controller outputs can be reset (either manual or
automatic). After a reset is executed and the Safety Outputs (OSSDs) turn ON, the status of the monitor contacts are no longer
monitored and may change state. However, the monitor contacts must be closed within 250 milliseconds of the OSSD outputs going
from ON to OFF.
• Two-Channel Monitoring: an independent connection of closed monitor contacts that are forced-guided (mechanically linked) from
each device controlled by the Controller. Both EDM inputs must be closed before the Controller can be reset and the OSSDs can turn
ON. While the OSSDs are ON, the inputs may change state (either both open, or both closed). If the inputs remain in opposite states
for more than 250 milliseconds, a lockout will occur.
• No Monitoring: If no monitoring is desired, simply do not select either one-channel or the two-channel option. If the Controller does
not use the EDM function in category 3 or category 4 applications, the user must ensure that any single failure or accumulation of
failures of the external devices does not result in a hazardous condition and a successive machine cycle will be prevented.
CAUTION: . . . EDM Configuration
If the application does not require the EDM function, it is the user’s responsibility to ensure that this does not create a
hazardous situation.
CAUTION: . . . External Device Monitoring Hookup
It is strongly recommended that at least one normally closed, forced-guided monitoring contact of each MPCE or
external device be wired in order to monitor the state of the MPCEs (as shown in the hookup figures). If this is done,
proper operation of the MPCEs will be verified. MPCE monitoring contacts must be used in order to maintain control
reliability.
SC22-3/-3E Safety Controller Instruction Manual
40 www.bannerengineering.com - tel: 763-544-3164 P/N 133487 rev. C