The safety mat, its Safety Controller, and any output signal switching devices must meet, at a minimum, the Category 1
safety requirements. See ISO 13856-1 (EN 1760-1) and ISO 13849-1 (EN 954-1) for relevant requirement details.
The Safety Controller is designed to monitor 4-wire safety mats and is not compatible with two-wire devices
(mats, sensing edges, or any other devices with two wires and a sensing resistor).
4-Wire
This circuit typically meets ISO 13849-1 Category 2 or Category 3
requirements depending on the safety rating and installation of the mat(s).
The Safety Controller enters a Lockout mode when an open wire, a short to
0 V, or a short to another source of power is detected.
6.4.10 Muting Sensor
Safety device muting is an automatically controlled suspension of one or more safety input stop signals during a
portion of a machine operation when no immediate hazard is present or when access to the hazard is safeguarded. Muting
sensors can be mapped to one or more of the following safety input devices:
• Safety gate (interlocking) switches
• Optical sensors
• Two-hand controls
• Safety mats
• Protective stops
US and International standards require the user to arrange, install, and operate the safety system so that personnel are
protected and the possibility of defeating the safeguard is minimized.
Examples of Muting Sensors and Switches
WARNING: Avoid Hazardous Installations
Two or four independent position switches must be properly adjusted or positioned so that
they close only after the hazard no longer exists, and open again when the cycle is complete
or the hazard is again present. If the switches are improperly adjusted or positioned, injury
or death may result.
The user is responsible to satisfy all local, state, and national laws, rules, codes, and regulations
relating to the use of safety equipment in any particular application. Make sure that all appropriate
agency requirements have been met and that all installation and maintenance instructions contained in
the appropriate manuals are followed.
Photoelectric Sensors (Opposed Mode)
Opposed-mode sensors should be configured for dark operate (DO) and have open (non-conducting) output contacts in a
power Off condition. Both the emitter and receiver from each pair should be powered from the same source to reduce the
possibility of common mode failures.
Photoelectric Sensors (Polarized Retroreflective Mode)
The user must ensure that false proxying (activation due to shiny or reflective surfaces) is not possible. Banner low profile
sensors with linear polarization can greatly reduce or eliminate this effect.
Use a sensor configured for light operate (LO or N.O.) if initiating a mute when the retroreflective target or tape is
detected (home position). Use a sensor configured for dark operate (DO or N.C.) when a blocked beam path initiates the
muted condition (entry/exit). Both situations must have open (non-conducting) output contacts in a power Off condition.
Positive-Opening Safety Switches
Two (or four) independent switches, each with a minimum of one closed safety contact to initiate the mute cycle, are
typically used. An application using a single switch with a single actuator and two closed contacts may result in an unsafe
situation.
Inductive Proximity Sensors
Typically, inductive proximity sensors are used to initiate a muted cycle when a metal surface is detected. Do not use two-
wire sensors due to excessive leakage current causing false On conditions. Use only three- or four-wire sensors that have
discrete PNP or hard-contact outputs that are separate from the input power.
XS/SC26-2 Safety Controller
80
To Next Page
Loading...
Need help?
General
