Securitron TSH - Manual (Page 6)

PN# 500-17700
Page 6 Rev. C, 08/11
5. OPERATIONAL SECURITY CONSIDERATIONS
In the typical use of the Touch Sense Handle, it provides free egress from the interior protected
area. The electric lock secures against unauthorized entry from outside. It is of important
concern that persons on the outside cannot activate the interior release device from the outside.
This is a common problem with other interior release devices. For instance, if a panic bar with
switch is used, it is possible to trip it from the outside if the intruder can introduce a coat hanger
in between the door and frame. Aluminum frame glass doors tend to allow this more than other
types. Similarly, microwave detectors used on the inside can sometimes be activated from the
outside if the door is vibrated strongly.
The Touch Sense Handle is more secure with respect to the outside. To assure this security,
however, the user must be made aware of certain operational characteristics. The sensor
functions by setting up an oscillating electric field which conforms along any metal surface that
contacts the sensor's antenna wire. In the Touch Sense Handle it is the handle itself that carries
the field. The electric field is disturbed by the near proximity of ionized fluids within the body,
which form a conductive mass. It is this mass that the sensor detects. As a proximity device,
the handle is sensitive to the closeness of the mass. For example, if a person wearing gloves
touches the handle with his finger tip, the door will generally not release. When the gloved hand
is wrapped around the handle in normal use, the door will release because the conductive mass
of the hand is in much closer contact with the handle.
The main security concern regarding outside entry is if a person could introduce a metal wire
from the outside and make metal to metal contact with the handle. The field could then
propagate along the wire and be activated by the intruder's hand. In practice, this is unlikely.
The handle is anodized and therefore insulated so it will not make contact with the wire. The
intruder would have to scratch away the anodization which requires both effort and knowledge.
Also the field propagates weakly along a thin wire. If, however, high security from the outside is
critical in the application, the sensitivity of the TSH should be set as low as satisfies the exit
performance requirements.
6. SENSOR REPLACEMENT
Should it ever be necessary to replace the sensor circuit board, it is done as follows: Remove
the two screws holding the plaque and slide out the plaque. Remove the two large flathead
Phillips machine screws and carefully remove the aluminum handle from the plastic base. As
you are removing the aluminum handle, note that it is connected to the base via a ring terminal
with brown wire screwed into the handle but soldered into the sensor circuit board. Unscrew the
ring terminal from the handle and put the handle aside. Next unscrew the red redundant backup
switch from the base. The backup switch is part of the sensor circuitry and the board will not
function without it. Finally, note that the board is held to the base via two Phillips machine
screws. Remove these screws and the board is ready for replacement.
APPENDIX A
TROUBLESHOOTING
PROBLEM- The door will not release when the handle is touched.
To monitor operation of the handle, it is quite easy to hear the relay click when the handle is
touched. Alternately, if you remove the plaque, you can monitor the LED which comes on when
the handle senses touch. If you don't hear a click (or see the LED come on), try the
backup switch. If the door does not release from the backup switch, it is almost certain that the
overall wiring of the installation is at fault. If the door releases from the backup switch, the
general wiring is correct but the sensor is not reading your touch. Make sure you understand
section 3.6 on how to adjust sensitivity of the handle. It may be set too low. Another fault
could be that the sensor itself is not receiving 12-24 DC power on the red and black wires.
Check the power supply and, be sure the input polarity is correct. Also, even if power is
being applied on the red and black wires, it's possible that it's not getting into the sensor. Check
the connector block that plugs into the sensor card for loose wires. Finally, it is possible that the
ring terminal that connects the sensor to the handle itself has come loose. See Figure 2.
If you can hear this click (or see the LED come on) and the door does not release, try the
backup switch. If the door still doesn't release, the problem must be in the installation wiring as
it is nearly impossible to have a failed sensor relay and backup switch at the same time. Review
your wiring to make sure the sensor is correctly applied in the circuit. If you hear the click but