Banner Safety Mat Monitoring Modules User Manual

Page 3

The Safety Module is powered by either a 12-24V dc supply at 4W or an ac supply (115V ac, model SM-GA-5A, or 230V ac, model SM-HA-5A) at 7VA. 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 (i.e., 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 which 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 24V dc or an ac power supply, and no more than 25 ohms when the Module is supplied by 12V dc.

The resistance between the channels when shorted together (i.e., when an individual steps on the mat) can not exceed 150 ohms (24V dc or an ac supply) or 10 ohms
(12V 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 ele-
ments (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 could result in serious injury or death.

NOTE: The minimum amount of time for the Module to detect a STOP condition is 15 ms. 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 mini-
mum 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 20V 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.

SM-xA-5A Safety Mat Monitoring Modules

P/N 122364 rev. C