P/N 69761 rev. B
13
Banner Engineering Corp.
•
Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
PICO-GUARD Controller
Instruction Manual
For this reason, single channel control interfacing should
be used only in installations where FSD safety stop circuits
and the MPCEs are mounted within the same control panel,
adjacent to each other, and are directly connected to each
other; or where the possibility of such a failure can be
excluded. If this can not be achieved, then dual channel control
should be used.
Methods to exclude the possibility of these failures include, but
are not limited to:
• Physically separating interconnecting control wires from each
other and from secondary sources of power.
• Routing interconnecting control wires in separate conduit,
runs, or channels.
• Locating all elements (modules, switches, and devices under
control) within one control panel, adjacent to each other, and
directly connected with short wires.
• Properly installing multi-conductor cabling and multiple wires
through strain-relief fittings. (Over-tightening of a strain-relief
can cause short-circuits at that point.)
• Using positive-opening or direct-drive components, installed
and mounted in a positive mode.
3.9.3 EDM Inputs
External Device Monitoring
It is strongly recommended that one normally closed,
forced-guided monitoring contact of each MPCE (or FSD)
be connected to EDM inputs (see Figures 3-7 to 3-10). If
this is done, proper operation of the MPCEs will be verified.
Monitoring MPCE contacts is one method of maintaining
control reliability.
External Device Monitoring Hookup:
Controller terminals
12-15 provide connection for the External Device Monitoring
inputs. External device monitoring (EDM) must be wired in one
of the three following configurations and must agree with the
controller’s EDM DIP switch settings (see Section 4.1). One-
and two-channel EDM are used when the PICO-GUARD OSSD
outputs directly control the energizing and de-energizing of the
guarded machine’s MPCEs.
•
One-channel monitoring
is a series connection of closed
monitor contacts that are forced-guided, mechanically linked
from each device controlled by PICO-GUARD. One-channel
monitoring uses EDM 1 input only. EDM 2 input must be
left open (no connection). At power up, EDM 1 input will be
verified to be in the closed state.
When the OSSD outputs have changed from ON to OFF, EDM 1
input will be verified to be in the closed state within 250 ms.
CAUTION . . .
EDM Monitoring
If the system is configured for No Monitoring,
it is the user’s responsibility to ensure that
this does not create a hazardous situation.
Safety Stop Circuits
A safety stop allows for an orderly cessation of motion for
safeguarding purposes, which results in a stopping of motion
and removal of power from the MPCEs (assuming this does
not create additional hazards). A safety stop circuit typically
comprises a minimum of two normally open (N.O.) contacts
from forced-guided, mechanically linked relays, which are
monitored (through EDM) to detect certain failures in order to
prevent the loss of the safety function. Such a circuit can be
described as a “safe switching point.” Typically, safety stop
circuits are either single channel, which is a series connection
of at least two N.O. contacts; or dual channel, which is a
separate connection of two N.O. contacts. In either method,
the safety function relies on the use of redundant contacts to
control a single hazard (if one contact fails ON, the second
contact will prevent the next cycle from occurring).
The interfacing of the safety stop circuits must be
accomplished so that the safety function can not be
suspended, overridden, or defeated, unless accomplished
in a manner at the same or greater degree of safety as the
machine’s safety related control system that includes the
PICO-GUARD.
The normally open safety outputs from an interface module
provide a series connection of redundant contacts that form
safety stop circuits for use in either single channel or dual
channel control. (See Figures 3-8 and 3-9.)
Dual Channel Control
Dual channel control provides the ability to electrically extend
the safe switching point beyond the FSD contacts. With proper
monitoring (i.e., EDM), this method of interfacing is capable
of detecting certain failures in the control wiring between the
safety stop circuit and the MPCEs. These failures include a
short-circuit of one channel to a secondary source of energy or
voltage, or the loss of the switching ability of one of the FSD
outputs. Such failures could lead to the loss of redundancy —
or to a complete loss of safety, if not detected and corrected.
The possibility of a failure to the wiring increases as the
physical distance between the FSD safety stop circuits and
the MPCEs increase, as the length or the routing of the
interconnecting wires increases, or if the FSD safety stop
circuits and the MPCEs are located in different enclosures.
For this reason, dual channel control with EDM monitoring
should be used in any installation where the FSDs are located
remotely from the MPCEs.
Single Channel Control
Single channel control, as mentioned, uses a series connection
of FSD contacts to form a safe switching point. After this point
in the machine’s safety-related control system, failures can
occur that would result in the loss of the safety function (such
as a short-circuit to a secondary source of energy or voltage).
Installation and Alignment
