Larco MAX1524 User manual

Datasheet
MAX1524 (12-24 V dc / 115 V ac operation) and MAX2324 (12-24 V dc / 230 V ac operation)
• Monitors one 4-wire safety mat, or multiple mats in series
• Selectable Automatic (Auto) Reset or Monitored Manual Reset
•Input monitoring circuit incorporates redundant microprocessors
• Plug-in terminal blocks
• Four normally open output switching channels for connection to control-
reliable power interrupt circuits and one normally closed auxiliary output
channel for status monitoring
• Two auxiliary solid-state outputs indicate state of internal relays K1 and
K2, and state of system (ON = normal operation)
• 6 amp safety output contacts; 5 amp aux. output contacts
• DIN-rail-mountable 45 mm-wide housing
• External device monitoring (one-channel EDM)
• Design complies with UL 991, ISO 13856-1, ISO 13849-1 (EN 954-1)
Category 4: Internal Module, or Category 3 with 4-wire Safety Mat
connected
WARNING: Not a Stand-Alone Safeguarding Device
This device is considered complementary equipment that is used to augment safeguarding that limits or
eliminates an individual's exposure to a hazard without action by the individual or others. Failure to
properly safeguard hazards according to a risk assessment, local regulations, and relevant
standards may lead to serious injury or death.
Models
Model Supply Voltage Outputs Output Rating
MAX1524 12 to 24 V dc or 115 V ac 4 Normally Open Safety
1 Normally Closed Aux.
2 Solid-State Aux.
N.O. Safety Outputs: 6 A
N. C. Aux. Outputs: 5 A
SS Aux Outputs: 100 mA
MAX2324 12 to 24 V dc or 230 V ac
Important... Read This Before Proceeding
The user is responsible for satisfying all local, state, and national laws, rules, codes, and regulations relating to the use of
this product and its application. ATEK Access Technologies has made every effort to provide complete application,
installation, operation, and maintenance instructions. Please direct any questions regarding the use or installation of this
product to the Customer Care Team at 800-523-6996.
The user is responsible for making sure that all machine operators, maintenance personnel, electricians, and supervisors
are thoroughly familiar with and understand all instructions regarding the installation, maintenance, and use of this
product, and with the machinery it controls. The user and any personnel involved with the installation and use of this
product must be thoroughly familiar with all applicable standards, some of which are listed within the specifications. ATEK
Access Technologies makes no claim regarding a specific recommendation of any organization, the accuracy or
effectiveness of any information provided, or the appropriateness of the provided information for a specific application.
MAX1524 and MAX2324 Safety Mat
Monitoring Modules
Original Document
122366 Rev. B 10 December 2015
122366

Overview
Safety Mat Monitor Modules MAX1524 and MAX2324 (the "Safety Module") are used to verify the proper operation of 4-
wire presence-sensing switching mats (sensors).
Multiple mats may be switched in series to one Safety Module. The Safety
Module provides the redundant safety outputs required for creating a
control-reliable safety circuit. The Safety Module has two functions:
• To monitor the conductive elements (plates) and the wiring of one or
more safety mat(s) for failures and prevent the machine from
restarting if any mat or the Module fails
• To provide a reset routine after the operator steps off the safety
mat. This prevents the controlled machinery from restarting
automatically after the mat is cleared. This necessary reset/restart
function is required by ANSI B11 and ANSI NFPA 79 machine safety
standards. If the Module is used in auto-reset mode, the reset/
restart function must be provided by the machine control system
NOTE: The Safety Module is not designed to monitor 2-
wire mats, bumpers, or edges (with or without sensing
resistors). Figure 1. Indicator and Terminal Locations
In operation, the Safety Module monitors the conductive elements (plates) of the pressure-sensitive mat for shorting of
those elements (that is, when the mat is stepped on) and certain faults, such as shorts to other sources of power or
ground (0 V), or open connecting wires. With a +24 V dc supply, Channel 1 (S11-S12) supplies > 20 V dc that is pulsed
low and Channel 2 (S21-S22) supplies < 2 V that is pulsed high; when these two channels are shorted together, the safety
output contacts open (13-14, 23-24, 33-34, and 43-44).
If a fault is detected, the Module will lock out, open its safety outputs, and indicate the problem on its LED display, which
can be diagnosed by using the troubleshooting table in this document. After repairing the fault, step on the mat and off it
again to clear the lockout condition (or cycle power). If the fault has been cleared and no other faults exist, the Fault LED
turns OFF and the Module can be reset (if configured for Auto Reset, the safety outputs will turn ON immediately).
The output relays energize automatically if the Module is wired for Auto Reset mode, all sensors are clear, all faults are
removed or corrected, and power is applied. The Module requires a manual reset if it is wired for Manual Reset mode.
Application of Pressure-Sensitive Mats and Floors
Pressure-sensitive mats and pressure-sensitive floors must meet the requirements of the category and performance level
for which they are specified and marked. These requirements are defined in ISO 13849-1 (EN 954-1).
The Safety Module is designed to monitor 4-wire safety mats; it is not recommended to use two-wire devices (mats,
sensing edges, etc., with two wires and a "sensing" resistor). While the Module internally meets or exceeds ISO 13849-1
(EN 954-1) Category 4 requirements, the overall safety circuit performance is determined by the mat(s) or other sensor(s)
connected to the Module.
NOTE: Application of Safety Mats
Safety Mat application requirements vary for the level of control reliability or category and performance
level as described by ISO 13849-1 (EN 954-1) and ISO 13856. While ATEK Access Technologies always
recommends the highest level of safety in any application, the user is responsible to safely install,
operate, and maintain each safety system per the manufacturer's recommendations and
comply with all relevant laws and regulations.
Do not use safety mats as a tripping device to initiate machine motion (such as in a
presencesensing device initiation application), due to the possibility of unexpected start or re-start of
the machine cycle resulting from failure(s) within the mat and the interconnect cabling.
Do not use a safety mat to enable or provide the means to allow the machine control to start
hazardous motion by simply standing on the safety mat (for example, at a control station). This
type of application uses reverse/negative logic and certain failures (for example, loss of power to the
Module) can result in a false enable signal.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
2www.LARCO.com TEL: [phone] P/N 122366 Rev. B

Safety Circuit Integrity and ISO 13849-1 Safety Circuit Principles
Safety circuits involve the safety-related functions of a machine that minimize the level of risk of harm. These safety-
related functions can prevent initiation, or they can stop or remove a hazard. The failure of a safety-related function or its
associated safety circuit usually results in an increased risk of harm.
The integrity of a safety circuit depends on several factors, including fault tolerance, risk reduction, reliable and well-tried
components, well-tried safety principles, and other design considerations.
Depending on the level of risk associated with the machine or its operation, an appropriate level of safety circuit integrity
(performance) must be incorporated into its design. Standards that detail safety performance levels include ANSI B11.19
Performance Criteria for Safeguarding and ISO 13849-1 Safety-Related Parts of a Control System.
Safety Circuit Integrity Levels
Safety circuits in International and European standards have been segmented into Categories and Performance Levels,
depending on their ability to maintain their integrity in the event of a failure and the statistical likelihood of that failure.
ISO 13849-1 details safety circuit integrity by describing circuit architecture/structure (Categories) and the required
performance level (PL) of safety functions under foreseeable conditions.
In the United States, the typical level of safety circuit integrity has been called "Control Reliability". Control Reliability
typically incorporates redundant control and self-checking circuitry and has been loosely equated to ISO 13849-1 Category
3 or 4 and/or Performance Level “d” or “e” (see ANSI B11.19).
Perform a risk assessment to ensure appropriate application, interfacing/hookup, and risk reduction (see ANSI B11.0 or
ISO 12100). The risk assessment must be performed to determine the appropriate safety circuit integrity in order to
ensure that the expected risk reduction is achieved. This risk assessment must take into account all local regulations and
relevant standards, such as U.S. Control Reliability or European "C" level standards.
Fault Exclusion
An important concept within the requirements of ISO 13849-1 is the probability of the occurrence of a failure, which can
be reduced using a technique termed "fault exclusion." The rationale assumes that the possibility of certain well-defined
failure(s) can be reduced via design, installation, or technical improbability to a point where the resulting fault(s) can be,
for the most part, disregarded—that is, "excluded" in the evaluation.
Fault exclusion is a tool a designer can use during the development of the safety-related part of the control system and the
risk assessment process. Fault exclusion allows the designer to design out the possibility of various failures and justify it
through the risk assessment process to meet the requirements of ISO 13849-1/-2.
Safety Mat Requirements
WARNING: Risk Assesment
The level of safety circuit integrity can be greatly affected by the design and installation of the safety
devices and the means of interfacing of those devices. A risk assessment must be performed to
determine the appropriate level of safety circuit integrity to ensure the expected risk
reduction is achieved and all relevant regulations and standards are complied with.
The following are minimum requirements for the design, construction, and installation of four-wire safety mat sensor(s) to
be interfaced with the Safety Mat Monitoring Module. These requirements are a summary of standards ISO 13856-1 and
ANSI/B11.19. Review all relevant applicable regulations and standards and apply the Module and any sensors in full
compliance.
Design and Constructions
The safety mat system [Safety Module, sensor(s), and any additional devices] must have a response time that is fast
enough (less than 100 to 200 ms, depending on the relevant standard) to reduce the possibility of an individual stepping
lightly and quickly over the mat’s sensing surface, without being detected.
For a safety mat system, the minimum object sensitivity of the sensor must detect, at a minimum, a 30 kg (66 lb.) weight
on an 80 mm (3.125 in) diameter circular disk test piece, anywhere on the mat’s sensing surface, including at joints and
junctions. The effective sensing surface or area must be identifiable and can comprise one or more sensors. The safety
mat supplier should state this minimum weight and diameter as the minimum object sensitivity of the sensor.
User adjustments to actuating force and response time are not allowed (ISO 13856-1). The sensor should be
manufactured to prevent any reasonably foreseeable failures (for example, oxidation of the contact elements) which could
cause a loss in sensitivity.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
P/N 122366 Rev. B www.LARCO.com TEL: [phone]

The sensor must meet a minimum environmental rating of IP54. When the sensor is specified for immersion in water, the
sensor’s minimum environmental rating must be IP67. Special attention may be required to the interconnect cabling;
wicking action may result in the ingress of liquid into the mat, possibly causing loss of sensor sensitivity. The termination
of the interconnect cabling may need to be located in an enclosure that has an appropriate environmental rating.
The sensor must not be adversely affected by the environmental conditions for which the system is intended. The effects
on the sensor of liquids and other substances which can be expected must be taken into account. For example, long-term
exposure to some liquids can cause degradation or swelling of the sensor’s housing material, resulting in an unsafe
condition.
The sensor’s top surface should be a lifetime non-slip design, or otherwise minimize the possibility of slipping, under the
expected operating conditions.
The four-wire connection between the Module interconnect cables and the sensor must withstand dragging or carrying the
sensor by its cable without failing in an unsafe manner (for example, broken connections due to sharp pulls, steady pulls,
or continuous flexing). If not, an alternate means must be employed to avoid such a failure, for example, a cable which
disconnects without damage and results in a safe situation.
Installation
The mounting surface quality and preparation for the sensor must meet the requirements stated by the sensor’s
manufacturer. Irregularities in the floor (or other mounting surfaces) may impair the function of the sensor and therefore
should be reduced to an acceptable minimum.
The mounting surface should be level and clean. Avoid the collection of fluids under or around the sensor. Prevent the risk
of failure due to build-up of dirt, turning-chips, or other material under the sensor(s) or the associated hardware. Give
special consideration to joints between sensors to ensure that foreign material does not migrate under or into the sensor.
Immediately repair or replace any damage (for example, cuts, tears, wear, or punctures) to the outer insulating jacket of
the interconnect cable (in the presence of fluids) or to any part of the exterior of the sensor. Ingress of material (including
dirt particles, insects, fluid, moisture, or turning-chips) which may be present near the mat can cause the sensor to
corrode or to lose its sensitivity.
Routinely inspect and test the sensor(s) per the manufacturer’s recommendations. Care must be taken not to exceed
operational specifications (for example, the maximum number of switching operations).
Securely mount the sensor(s) to prevent inadvertent movement (creeping) or unauthorized removal. Methods include (but
are not limited to) secured edging or trim, tamper-resistant or one-way fasteners, and recessed flooring or mounting
surface, in addition to the size and weight of large mats.
Install the sensor(s) to minimize tripping hazards (particularly towards the hazard). A tripping hazard may exist when the
difference in height of an adjacent horizontal surface is 4 mm (1/8 in) or more. Minimize tripping hazards at joints,
junctions, edges, and when additional coverings are used. Methods include a ground-flush installation of the sensor, or a
ramp that does not exceed 20° from horizontal. Use contrasting colors or markings to identify ramps and edges.
Size and position the safety mat system so that persons cannot enter the hazardous area without being detected, and can
not reach the hazard before the hazardous conditions have ceased. Additional guards or safeguarding devices may be
required to ensure that exposure to the hazard(s) is not possible by reaching over, under or around the device’s sensing
surface.
Take into account the possibility of easily stepping over the sensing surface without being detected. ANSI and international
standards require a minimum depth of field of the sensor surface (the smallest distance between the edge of the mat and
hazard) to be between 750 mm to 1200 mm (30 in to 48 in), depending on the application and the relevant standard.
Prevent the possibility of stepping on machine supports or other physical objects to bypass or climb over the sensor.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
4www.LARCO.com TEL: [phone] P/N 122366 Rev. B

Separation Distance
As a stand-alone safeguard, the sensor must be installed at a
separation distance (safety distance) such that the exterior edge
of the sensing surface is at or beyond the safety distance, unless
solely used to prevent start/restart or solely used for clearance
safeguarding (see ANSI B11.19).
The separation distance required for an application depends upon
several factors, including the speed of the hand (or individual),
the total system stopping time (which includes several response
time components), and the depth penetration factor. The user
must refer to the relevant standard to determine the appropriate
distance or means to ensure that individuals can not be exposed
to the hazard(s).
One formula used to calculate separation distance (Ds) is:
Ds = K × (Ts + Tr) + Dpf
where:
K = the OSHA-recommended hand speed constant of 1600 mm
(63 in) per second (see NOTE below);
Ts = the overall stop time of the machine, measured from the
application of the “stop” signal to the final ceasing of all motion
(including stop times of all relevant control elements, and
measured at maximum machine velocity).
Tr = the response time of the safety mat system: Module
response time plus the response time of the sensor(s), as stated
by the manufacturer.
Dpf = the added distance due to depth penetration factor: 1.2 m
(48 in)
Hazardous
Zone
or
Area
Safety Mat
Ds
K(Ts + Tr) Dpf
Figure 2. Determining Separation Distance for the Safety Mat
NOTE: The OSHA-recommended hand-speed constant (K) has been determined by various studies, and
although these studies indicate speeds of 1600 mm (63 in) per second to more than 2540 mm (100 in)
per second, they are not conclusive determinations. The employer should consider all factors, including
the physical ability of the operator, when determining the value of K to be used.
If an individual can cross completely over the sensor and be no longer detected, supplemental safeguarding or other
means should be used to prevent unexpected startup and exposure to a hazard. At a minimum, the safety mat system (or
the machine control) must be manually reset and require re-initiation of the normal actuating means prior to the start or
re-start of the machine cycle.
Mechanical Installation
The Safety Module must be installed inside an enclosure.
It is not designed for exposed wiring. It is the user’s responsibility to house the Safety Module in an enclosure with NEMA 3
(IEC IP54) rating, or better. The Safety Module mounts directly to standard 35 mm DIN rail.
Heat Dissipation Considerations: For reliable operation, ensure that the operating specifications are not exceeded. The
enclosure must provide adequate heat dissipation, so that the air closely surrounding the Module does not exceed the
maximum operating temperature stated in the Specifications. Methods to reduce heat build-up include venting, forced
airflow (for example, exhaust fans), adequate enclosure exterior surface area, and spacing between modules and other
sources of heat.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
P/N 122366 Rev. B www.LARCO.com TEL: [phone]

Remove or Install a Terminal Block
To remove a terminal block:
1. Insert a small screwdriver into the slot between the cover label and the
terminal block.
2. Using the screwdriver, pry to loosen the terminal block.
3. Slide the terminal block out from the face of the module.
To reinsert the terminal block:
1. Carefully slide the dovetail on the terminal block into the slot on the housing.
2. Press on the terminal block until it is fully seated. A "click" should be heard
when the terminal block is properly installed.
POWER
FAULT
CH. 1
CH. 2
K1
K2
51 52
13
K1
K2
14 23
A1 A2 B1 S11 S12 S21 S22
B2
24 33 34 43 44
Y30 Y31 Y32 Y35 51 52
S31 S32 S33 S34 S32 S35
Figure 3. Remove the Terminal Block
Electrical Installation
WARNING: Shock Hazard and Hazardous Energy
Always disconnect power from the safety system (for example, device, module, interfacing,
etc.) and the machine being controlled before making any connections or replacing any
component.
Electrical installation and wiring must be made by Qualified Personnel1and must comply with the
relevant electrical standards and wiring codes, such as the NEC (National Electrical Code), ANSI
NFPA79, or IEC 60204-1, and all applicable local standards and codes.
Lockout/tagout procedures may be required. Refer to OSHA 29CFR1910.147, ANSI Z244-1, ISO
14118, or the appropriate standard for controlling hazardous energy.
Electrical installation must be made by qualified personnel and must comply with NEC (National Electrical Code), ANSI/
NFPA 79 or IEC/EN 60204-1, and all applicable local standards. It is not possible to give exact wiring instructions for a
device that interfaces to a multitude of machine control configurations. The following guidelines are general in nature.
Perform a risk assessment to ensure appropriate application, interfacing/hookup, and risk reduction (see ANSI B11.0 or
ISO 12100).
The Safety Module is powered by either a 12-24 V dc supply at 4 W or an ac supply (115 V ac, model MAX1524, or 230 V
ac, model MAX2324) at 7 VA. The sensor circuit, which monitors the conductive elements (plates) of the safety mat,
consists of two channels (A and B) that issue a stop command (that is, open the safety outputs) when an individual steps
onto the safety mat, shorting the two channels together.
It is not possible to give exact wiring instructions for a Safety Module that interfaces to a multitude of machine control
configurations. The following guidelines are general in nature.
Since the Safety Module functions by detecting the short circuit between the channels, resistance to electrical current flow
in the contact monitoring circuit impacts the operation and the safety of the system. Total resistance includes contact
resistance of the internal mat contacts, the number of mats in the circuit, and the wire resistance of the interconnect
cables and connections.
The only limitation on the number of mats that can be connected in series is the amount of resistance. The total resistance
within each channel can not exceed 250 ohms when the Module is supplied by 24 V dc or an ac power supply, and no more
than 25 ohms when the Module is supplied by 12 V dc.
The resistance between the channels when shorted together (that is, when an individual steps on the mat) can not exceed
150 ohms (24 V dc or an ac supply) or 10 ohms (12 V dc supply).
WARNING: Multiple Safety Mats
Whenever two or more safety mats are connected to the same Safety Mat Monitor Module, the
corresponding conductive elements (plates) of all mats must be connected together in series, as shown
in the hookup drawing. Never connect the conductive elements (plates) of multiple safety mats
in parallel; this defeats the ability of the Safety Module to detect open connection wires to
each mat, which would create an unsafe condition that may result in serious injury or death.
1A person who, by possession of a recognized degree or certificate of professional training, or who, by extensive knowledge, training and experience, has
successfully demonstrated the ability to solve problems relating to the subject matter and work.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
6www.LARCO.com TEL: [phone] P/N 122366 Rev. B

NOTE: The minimum amount of time for the Module to detect a STOP condition is 15 milliseconds. This
"recovery time" (OFF state) is required for the internal integrity tests to complete, allowing a reliable
reset to occur. A lockout may occur if the Module is cycled too quickly. To clear the lockout, the inputs
must be re-cycled, meeting the minimum recovery time requirements.
Safety Mat Device Checkout - Prior to Module Connection
Before connecting the safety mat to the Module, verify the installation does not exceed the maximum resistance
specification. Check the mat with an ohmmeter to verify that none of the following values are exceeded.
1. Check the leadwire resistance.
a) Keeping track of which wire goes to which terminal, disconnect all 4 wires from the terminal blocks.
b) Measure and record the resistance between the wires going to terminals S11 and S12: ________ (=Ra)
c) Measure and record the resistance between the wires going to terminals S21 and S22: ________ (=Rb)
d) Review the values for Ra and Rb.
If both Ra and Rb
are Then
Less than 50 ohms The lead resistance is acceptable for all supply voltages; check the mat resistance next. If it
is 50 ohms or more for either, continue below.
Less than 500 ohms The lead resistance is acceptable for an AC supply and for a DC supply >20 V. If resistance is
acceptable for your supply, check the mat resistance next. If resistance is not acceptable,
lower the lead resistance by shortening the leadwires or by increasing the wire diameter.
Recheck Ra and Rb.
2. Check the mat resistance.
a) Step on the mat in various locations while taking the measurements listed below.
b) Measure and record the highest observed resistance between S11 and S21: ________ (=Rc)
c) Measure and record the highest observed resistance between S21 and S22: ________ (=Rd)
d) Review the values for Rc and Rd.
If both Rc and Rd are Then
Less than 10 ohms The mat and leadwire resistance is acceptable for all supply
voltages and the safety mat checkout is complete.
Less than 150 ohms AND you are using an
AC supply or DC supply greater than 20 V dc The mat and leadwire resistance is acceptable and the safety mat checkout is complete.
Any other value If resistance is not acceptable, proceed to the next step.
3. Connect the ohmmeter to the wires to be connected to S11-S12 (Channel A), and note the resistance.
4. Connect the ohmmeter to the wires to be connected to S21-S22 (Channel B), and note the resistance.
5. Perform the following calculation: Rm = (Rc + Rd - Ra - Rb)/2.
If Rm is: Then
Less than 10 ohms The mat resistance is acceptable for all supply voltages; the safety mat
checkout is complete.
Less than 150 ohms AND you are using
an AC supply or DC supply greater than
20 V dc
The mat resistance is acceptable and the safety mat checkout is
complete.
Any other value The resistance in the mat is too high for safe operation. Replace the
safety mat. Repeat the mat resistance checkout for the new mat.
WARNING: Safety Mat Resistance Values
Exceeding the maximum resistance between the monitoring channels (usually due to
degradation of the mat) can result in the increase of response time or complete loss of the
sensing function of the safety mat, when it is stepped on (shorted). This can result in serious
injury or death.
Exceeding the maximum resistance within a contact monitoring channel can result in the Module issuing
a stop command (opening the safety outputs) when no person is present.
To ensure proper operation, verify the quality and specifications of the mat being connected
to this Module, and perform periodic checks of the safety mat's resistance, as described in
the Safety Mat Initial Checkout.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
P/N 122366 Rev. B www.LARCO.com TEL: [phone]

Connection of Reset Switch
The reset circuit switch can be any mechanical switch, such as a normally open momentary switch, or a two-position key
switch. The reset switch must be capable of reliably switching 12 to 30 V dc at 20 to 50 milliamps. As shown in the hookup
drawings, the reset switch connects between Safety Module terminals S33 and S34.
The reset switch must be located outside of – and not be accessible from – the area of dangerous motion, and must be
positioned so that any area of dangerous motion may be observed by the switch operator during the reset procedure. See
warning below.
WARNING: Reset Switch Location
All reset switches must be accessible only from outside, and in full view of, the hazardous
area. Reset switches must also be out of reach from within the safeguarded space, and must
be protected against unauthorized or inadvertent operation (for example, through the use of
rings or guards). If any areas are not visible from the reset switch(es), additional means of
safeguarding must be provided. Failure to do so may result in serious bodily injury or death.
Automatic Reset Mode
The Safety Module may be configured (via hookup) for automatic reset. If no MSC contacts are monitored, install a jumper
between terminals S32 and S35 (see hookups). The Safety Module will reset (and its outputs energize) as soon as the
switch returns to its armed (closed-contact) position.
Automatic reset is useful for some automated processes. However, if automatic reset is used, it is necessary to
provide a means of preventing resumption of hazardous machine motion, until an alternate reset procedure is
performed. The alternate procedure must include a reset/restart switch, located outside the area of dangerous motion
and positioned so that any area of dangerous motion may be observed by the switch operator during the reset procedure.
See Warning.
WARNING: Reset Routine Required
U.S. and international standards require that a reset routine be performed after clearing the cause of a
stop condition (for example, arming an E-stop button, closing an interlocked guard, etc.). Allowing the
machine to restart without actuating the normal start command/device can create an unsafe
condition which may result in serious injury or death.
Connection to the Machine to be Controlled
The machine hookup diagram shows a generic connection of the Safety Module's redundant output circuits to the master
stop control elements (MSCs). An MSC is defined as an electrically powered device, external to the Safety Module, which
stops the machinery being controlled by immediately removing electrical power to the machine and (when necessary) by
applying braking to dangerous motion. This stopping action is accomplished by removing power to the actuator of either
MSC.
External Device Monitoring
To satisfy the requirements of Control Reliability (OSHA and ANSI), Category 3 and 4 of ISO 13849-1 (EN 954-1), the
Master Stop Control Elements (MSCs) must each offer a normally closed, forced-guided (mechanically linked) monitor
contact. Connect one normally closed monitor contact from each master stop control element in series to S31 and S32.
In operation, if one of the switching contacts of either MSC fails in the energized condition, the associated monitor contact
will remain open. Therefore, it will not be possible to reset the Safety Module. If no MSC-monitor contacts are monitored, a
jumper must be installed between terminals S31-S32, as shown in the hookup drawings. It is the user's responsibility to
ensure that any single failure will not result in a hazardous condition and will prevent a successive machine cycle.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
8www.LARCO.com TEL: [phone] P/N 122366 Rev. B

*
*
12-24V dc
or
115V ac or 230V ac
(depending on model)
Reset
Switch
Jumper for Auto Reset
MSC1 MSC3
MSC2 MSC4
L2
B2
MSC1
MSC2
Machine
Master Stop
Control
Elements
*Arc suppressors
(see WARNING)
Non-safety
Auxiliary
Monitor Contact
12-24V dc
System OKOutputs
Energized
Non-safety
Monitor Outputs
100 mA max.
each Output
K1A
6A max.
K2A
K1B
6A max.
K2B
K1C
6A max.
K2C
K1D
6A max.
K2D
*
*
MSC3
MSC4
MAX1524
for 12-24/115V
MAX2324
for 12-24/230V
B1
S11
S12
S22
S21
S34
S33
S32
S35
13 14
23 24
33 34
43 44
51 52
Y31
Y32 Y35
Y30
A2
S32
S31
A1
L1
Machine
Control
Circuits
dc common
+V
dc common
+V
MSC
Monitor
Contacts
or Jumper
Mat
5A max.
K1E K2E
S11
S12
S22
S21
Mat #nMat #1
Series Connection of Multiple Safety Mats
The number of mats is limited by the total
series resistance per input channel. See
section, “Safety Mat Device Checkout” and
warning, ”Safety Mat Resistance Values.”
Figure 4. Hookup to a Four-Wire Safety Mat
MAX1524 and MAX2324 Safety Mat Monitoring Modules
P/N 122366 Rev. B www.LARCO.com TEL: [phone]

WARNING: Wiring of Arc Suppressors
If arc suppressors are used, they MUST be installed as shown across the actuator coil of the stop
control elements (MSCs or MPCEs). NEVER install suppressors directly across the output
contacts of the Safety Device or Module. It is possible for suppressors to fail as a short circuit. If
installed directly across the output contacts, a short-circuited suppressor creates an unsafe
condition which may result in serious injury or death.
WARNING: Interfacing MSCs
Do not wire an intermediate device(s) (for example, PLC, PES, PC) between the Safety Module outputs
and the Master Stop Control Element it switches in such a manner that in the event of a failure there is
a loss of the safety stop command, or in such a manner that the safety function can be suspended,
overridden, or defeated, unless accomplished with the same or greater degree of safety.
Whenever forced-guided, mechanically linked relays are added as intermediate switching devices, a
normally closed (N.C.) forced-guided monitor contact from each relay must be added to the series
feedback loop between Safety Module terminals S31 and S32.
Overvoltage Category II and III Installations (EN50178 and IEC60664-1)
The Safety Module is rated for Overvoltage Category III when voltages of 1 V to 150 V ac/dc are applied to the output
relay contacts. It is rated for Overvoltage Category II when voltages of 151 V to 250 V ac/dc are applied to the output
relay contacts and no additional precautions are taken to attenuate possible overvoltage situations in the supply voltage.
The Module can be used in an Overvoltage Category III environment (with voltages of 151 V to 250 V ac/dc) if care is
taken either to reduce the level of electrical disturbances seen by the Module to Overvoltage Category II levels by
installing surge suppressor devices (for example, arc suppressors), or to install extra external insulation in order to isolate
both the Safety Module and the user from the higher voltage levels of a Category III environment.
For Overvoltage Category III installations with applied voltages from 151 V to 250 V ac/dc applied to the
output contact(s): the Safety Module may be used under the conditions of a higher overvoltage category where
appropriate overvoltage reduction is provided. Appropriate methods include:
•An overvoltage protective device
• A transformer with isolated windings
• A distribution system with multiple branch circuits (capable of diverting energy of surges)
• A capacitance capable of absorbing energy of surges
• A resistance or similar damping device capable of dissipating the energy of surges
When switching inductive ac loads, it is good practice to protect the Safety Module outputs by installing appropriately-sized
arc suppressors. However, if arc suppressors are used, they must be installed across the load being switched (for example,
across the coils of external safety relays), and never across the Safety Module’s output contacts (see WARNING, Arc
Suppressors).
Auxiliary Monitor Contact/Solid-State Monitor Outputs Connection
The action of the auxiliary monitor contact, terminals 51-52, inversely "follows" the action of the safety outputs. Two
additional solid-state monitor outputs (at terminals Y32 and Y35) each are capable of switching up to 100 mA at 12- 24 V
dc. The output at terminal Y32 follows the action of the output circuits (K1 and K2); the output at terminal Y35 opens (low
signal) when there is a loss of power or a fault is detected. These outputs are to be used only for nonsafety
functions (typically, to communicate the status of the Safety Module to a programmable logic controller). See the
appropriate figure for wiring information.
Safety Mat Module Initial Checkout Procedure
WARNING:
Checkouts for Multiple Safety Devices. If more than one safety mat is series-connected to one
Safety Mat Monitor Module, run this checkout procedure individually for each mat.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
10 www.LARCO.com TEL: [phone] P/N 122366 Rev. B

CAUTION: Disconnect Power Prior to Checkout
Before performing the initial checkout procedure, make certain all power is disconnected
from the machine to be controlled.
Dangerous voltages may be present along the Safety Module wiring barriers whenever power to the
machine control elements is On. Exercise extreme caution whenever machine control power is
or may be present. Always disconnect power to the machine control elements before opening
the enclosure housing of the Safety Module.
1. Remove power to the machine control elements, if it is already connected.
2. Apply force to the mat’s sensing area, using a test piece as outlined in the mat manufacturer’s literature, or the
appropriate standard.
3. Apply input power to the Safety Mat Monitor Module at terminals A1 and A2 or B1 and B2. Verify that only the Power
indicator LED is ON.
4. Remove the test piece from the safety mat (clear the mat sensing area).
5. Manual Reset mode: Ch1 and Ch2 indicators should be flashing. Close and reopen the Reset switch.
6. Verify that the Ch1 and Ch2 indicators both come ON. If only one indicator comes ON or if any indicator is flashing,
refer to the Troubleshooting section for more information. Return to step 2 after correcting the problem.
7. Apply force in several locations (using a test piece) to the mat’s sensing area, per the mat manufacturer’s
recommendations. Verify that the Ch1 and Ch2 indicators turn OFF simultaneously. If either indicator does not go OFF,
disconnect the input power and check all wiring. Return to step 2 after correcting the problem.
8. Repeat for each safety mat individually.
9. Close and secure the enclosure. Apply power to the machine control elements and perform the following Periodic
Checkout Procedure.
Safety Mat System Periodic Checkout Procedure
Verify the functioning of the safety mat monitoring system periodically to ensure proper operation (see also the machine
manufacturer’s recommendations).
WARNING:
Checkouts for Multiple Safety Devices. If more than one safety mat is series-connected to one Safety
Mat Monitor Module, run this checkout procedure individually for each mat.
1. With the machine running, apply force to the mat’s sensing area, using a test piece as described in the mat
manufacturer’s literature, or the appropriate standard. Verify that the machine stops within the expected time period.
2. Remove the test piece from the safety mat. Verify that the machine does not restart.
3. Close and then open the Reset switch (if using Manual Reset mode). Verify that the machine cycle can be restarted by
normal initiation.
4. Repeat for each safety mat individually.
Troubleshooting
Use the LED display to help diagnose the problem. After fixing the fault:
•Manual Reset configured — step ON and OFF the mat to clear the lockout.
• Auto Reset configured — the outputs turn ON immediately.
The Fault LED turns OFF if the proper repair has been made.
Condition Indicator Status Possible Causes or Solution
Module will not reset Power LED ON Waiting for manual reset:
• EDM monitoring contacts are not closed. Check MSCs.
• Check jumper at S32-S35 (auto reset) or S32-S33 (manual reset).
• Check reset button connection.
Fault LED OFF
Ch1 LED Flashing
Ch2 LED Flashing
No fault indicated Power LED ON Safety mat appears actuated:
• Check mat for damage or heavy debris.
• Check for proper wiring.
• Check for a short in the wiring.
Fault LED OFF
Ch1 LED OFF
Ch2 LED OFF
MAX1524 and MAX2324 Safety Mat Monitoring Modules
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Condition Indicator Status Possible Causes or Solution
No fault indicated Power LED ON Channel 1 open:
• Check wiring to S11-S12.
•Check connectors are properly seated.
Fault LED ON*
Ch1 LED OFF
Ch2 LED ON
No fault indicated Power LED ON Channel 2 open:
• Check wiring to S21-S22.
• Check connectors are properly seated.
Fault LED ON*
Ch1 LED ON
Ch2 LED OFF
Fault Power LED ON Possible temporary fault:
• Check for loose wiring.
• Actuate the mat to clear the fault.
Possible internal fault:
• Return to factory for repair or replacement.
Fault LED ON*
Ch1 LED ON
Ch2 LED ON
All LEDs OFF Possible fault in the machine control or wiring to the Module:
•Check input power connections or external fuses.
•Check connectors are properly seated.
Dim LEDs Power LED dim:
•Check power supply capacity and load.
Other LEDs dim:
•May glow during power-up (normal).
• Check power supply load and capacity.
*Fault LED Flickers This is normal while the Fault LED is ON.
MSCs do not energize Power LED ON Possible fault in machine control or an open circuit between machine control
and MSCs:
•Check continuity of safety outputs (for example, between terminals 13
and 14).
•Check control wires and connectors.
• Check MSCs
Fault LED OFF
Ch1 LED ON
Ch2 LED ON
Repairs
Contact ATEK Access Technologies for troubleshooting of this device. Do not attempt any repairs to this device; it
contains no field-replaceable parts or components. If the device, device part, or device component is determined to be
defective by Customer Care Team, they will advise you of the RMA (Return Merchandise Authorization) procedure.
Important: If instructed to return the device, pack it with care. Damage that occurs in return shipping
is not covered by warranty.
CAUTION: Abuse of Module After Failure
If an internal fault has occurred and the Module will not reset, do not tap, strike, or otherwise
attempt to correct the fault by a physical impact to the housing. An internal relay may have
failed in such a manner that its replacement is required.
If the Module is not immediately replaced or repaired, multiple simultaneous failures may
accumulate such that the safety function can not be guaranteed.
Specifications
Category Specification
Supply Voltage and
Current AI-A2: 115 V ac (model MAX1524) or 230 V ac (model MAX2324) ±15%, 50/60 Hz
BI-B2: 11 V dc to 27.6 V dc
Connect the Safety Module only to a SELV (safety extra-low voltage, for circuits without earth ground) or a PELV
(protected extra-low voltage, for circuits with earth ground) power supply, according to EN IEC 60950, NEC Class 2.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
12 www.LARCO.com TEL: [phone] P/N 122366 Rev. B

Category Specification
Power Consumption Approx. 4 W / 7 VA
Supply Protection Circuitry Protected against transient voltages and reverse polarity
Overvoltage Category Output relay contact voltage of 1 V to 150 V ac/dc: category III
Output relay contact voltage of 151 V to 250 V ac/dc: category III, if appropriate overvoltage reduction is provided, as
described earlier.
Pollution Degree 2
Relay Outputs 4 normally open (N.O.) output channels and 1 normally closed (N.C.) output
Each normally open output channel is a series connection of contacts from two forced-guided (mechanically linked) relays,
K1-K2. The normally closed Aux. output channel is a parallel connection of contacts from two forced-guided relays, K1-K2.
Contacts: AgNi, 5 μm gold-plated
Low Current Rating: The 5 μm gold-plated contacts allow the switching of low current/low voltage. In these low-power
applications, multiple contacts can also be switched in series (for example, “dry switching”). To preserve the gold plating
on the contacts, do not exceed the following max. values at any time:
Min. voltage: 1 V ac/dc
Min. current: 5 mA ac/dc
Min. power: 5 mW (5 mVA)
Max. voltage: 60 V
Max. current: 300 mA
Max. power: 7 W (7 VA)
High Current Rating: If higher loads must be switched through one or more of the contacts, the minimum and maximum
values of the contact(s) changes to:
Minimum Maximum
Voltage: 15 V ac/dc N.O. Safety Contacts (13-14, 23-24, 33-34, 43-44):
250 V ac / 24 V dc, 6 A resistive
B300, Q300 (UL508)
Current: 250 mA ac/dc N.C. Auxiliary Contact (51-52): 250 V ac / 24 V dc, 5A
resistive
B300, Q300 (UL508)
Power: 5 W (5 VA)
Minimum Maximum — IEC60947-5-1
Voltage: 15 V ac/dc N.O. Safety Contacts:
AC-1: 250 V ac, 6 A; DC-1: 24 V dc, 6 A
AC-15: 230 V ac, 3 A; DC-13: 24 V dc, 4 A
Current: 250 mA ac/dc N.C. Auxiliary Contact:
AC-1: 250 V ac, 5 A; DC-1: 24 V dc, 5 A
AC-15: 230 V ac, 2 A; DC-13: 24 V dc, 4 A
Power: 5 W (5 VA)
Mechanical life: > 50,000,000 operations
Electrical life: 150,000 cycles @ 1500 VA; 1,000,000 cycles @ 450 VA; 2,000,000 cycles @ 250 VA; 5,000,000 cycles @
125 VA
NOTE: Transient suppression is recommended when switching inductive loads. Install
suppressors across load. Never install suppressors across output contacts (see Warning, Wiring
of Arc Suppressors).
Solid-State Outputs Two non-safety solid-state dc outputs
Output circuits require application of +12 to 24 V dc ± 15% at terminal Y31; dc common at Y30.
Max. switching current: 100 mA at 12 to 24 V dc
Both outputs are protected against short circuits.
Output at Y32 monitors state of outputs – conducts (output high) when both K1 and K2 are energized.
Output at Y35 conducts (output high) when in normal operation (no lockout).
Output Response Time 35 ms max. (25 ms typical)
MAX1524 and MAX2324 Safety Mat Monitoring Modules
P/N 122366 Rev. B www.LARCO.com TEL: [phone]

Category Specification
Input Requirements Safety mat normally open contact must be capable of switching 20 to 100 mA at 12 to 30 V dc; and must be closed > 25
ms for a valid stop command.
V ac or 24 V dc Supply: Max. lead resistance 250 ohms; max. contact resistance: 150 ohms.
12 V dc Supply: Max. lead resistance 25 ohms; max. contact resistance: 10 ohms.
Reset switch: must have one normally open contact capable of switching 20 to 50 mA at 12 to 30 V dc.
OFF-State Recovery Time 350 ms maximum
Indicators 3 green LED indicators: Power ON, Channel 1 (high side), Channel 2 (low side)
1 red LED indicator: indicates a fault condition (see Troubleshooting)
Construction Polycarbonate housing. Rated NEMA 1, IEC IP20
Mounting Mounts to standard 35 mm DIN rail track. Safety Module must be installed inside an enclosure rated NEMA 3 (IEC IP54),
or better.
Vibration Resistance 10 to 60 Hz at 0.35 mm peak displacement per UL 991
60 to 150 Hz at 5 g max.
Operating Conditions Temperature: 0 °C to +50 °C (+32 °F to +122 °F), (surrounding air)
90% at +50 °C maximum relative humidity (non-condensing)
Design Standards Cat. 4 PL e per EN ISO 13849-1; SIL 3 per IEC 61508 and IEC 62061
Certifications
Dimensions
All measurements are listed in millimeters (inches), unless noted otherwise.
84 mm
(3.3")
45 mm
(1.8")
118.0 mm
(4.6")
MAX1524 and MAX2324 Safety Mat Monitoring Modules
14 www.LARCO.com TEL: [phone] P/N 122366 Rev. B

Certifications and Standards
EC Declaration of Conformity (DoC)
ATEK Access Technologies herewith declares that the MAX1524 and MAX2324 Safety Mat Monitoring Modules are in
conformity with the provisions of the Machinery Directive 2006/42/EC and all essential health and safety requirements
have been met.
Representative in EU: Peter Mertens, Managing Director Banner Engineering Europe. Address: Park Lane, Culliganlaan 2F,
1831 Diegem, Belgium.
Standards and Regulations
The list of standards below is included as a convenience for users of this device. Inclusion of the standards below does not
imply that the device complies specifically with any standard, other than those specified in the Specifications section of this
manual.
U.S. Application Standards
ANSI B11.0 Safety of Machinery, General Requirements, and Risk Assessment
ANSI B11.19 Performance Criteria for Safeguarding
ANSI NFPA 79 Electrical Standard for Industrial Machinery
International/European Standards
ISO 12100 Safety of Machinery – General Principles for Design — Risk Assessment and Risk Reduction
IEC 60204-1 Electrical Equipment of Machines Part 1: General Requirements
ISO 13856-1 (EN1760-1), Safety of Machinery – Pressure-Sensitive Protective Devices
ISO 13855 (EN 999) The Positioning of Protective Equipment in Respect to Approach Speeds of Parts of the Human Body
IEC 61508 Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems
IEC 62061 Functional Safety of Safety-Related Electrical, Electronic and Programmable Control Systems
ISO 13849-1 (EN 954-1) Safety-Related Parts of Control Systems
IEC 60947-1 Low Voltage Switchgear – General Rules
IEC 60947-5-1 Low Voltage Switchgear – Electromechanical Control Circuit Devices
IEC 60947-5-5 Low Voltage Switchgear – Electrical Emergency Stop Device with Mechanical Latching Function
IEC 60529 Degrees of Protection Provided by Enclosures
ATEK Access Technologies Limited Warranty
Unless stipulated differently in Seller’s quotation, Goods are warranted for twelve (12) months from the date of shipment by Seller.
Products purchased by Seller from a third party for resale to Buyer (“Resale Products”) shall carry only the warranty extended by the
original manufacturer. Buyer agrees that Seller has no liability for Resale Products beyond making a reasonable commercial effort to
arrange for procurement and shipping of the Resale Products. If Buyer discovers any warranty defects and notifies Seller thereof in
writing during the applicable warranty period, Seller shall, at its option, repair or replace F.O.B. point of manufacture that portion of
the Goods found by Seller to be defective, or refund the purchase price of the defective portion of the Goods. All replacements or
repairs necessitated by inadequate maintenance, normal wear and usage, unsuitable power sources or environmental conditions,
accident, misuse, improper installation, modification, repair, use of unauthorized replacement parts, improper storage or handling, or
any other cause not the fault of Seller are not covered by this limited warranty, and shall be at Buyer’s expense. Seller shall not be
obligated to pay any costs or charges incurred by Buyer or any other party except as may be agreed upon in writing in advance by
Seller. All costs of dismantling, reinstallation and freight and the time and expenses of Seller’s personnel and representatives for site
travel and diagnosis under this warranty clause shall be borne by Buyer unless accepted in writing by Seller. Goods repaired and parts
replaced by Seller during the warranty period shall be in warranty for the remainder of the original warranty period or ninety (90)
days, whichever is longer. This limited warranty is the only warranty made by Seller and can be amended only in a writing signed by
Seller. THE WARRANTIES AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE. THERE ARE NO REPRESENTATIONS OR WARRANTIES
OF ANY KIND, EXPRESS OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE OR ANY OTHER MATTER WITH
RESPECT TO ANY OF THE GOODS OR SERVICES.
MAX1524 and MAX2324 Safety Mat Monitoring Modules
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