Banner DUO-TOUCH Two-Hand Control Modules - Manual (Page 6)

DUO-TOUCH
® – Models AT-..M-2A Two-Hand Control Modules
6
P/N 47550 rev. E
Banner Engineering Corp. • Minneapolis, MN U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Separation Distance
Both hand controls must be located far enough away from the nearest hazard point
that the operator cannot reach the hazard with a hand or other body part before the
hazardous motion ceases. This is the “separation distance,” and may be calculated as
follows:
For Part-Revolution Clutch Machinery
Where the machine and its controls allow the machine to stop motion during the
hazardous portion of the machine cycle, use the following formula:
Ds = K x (Ts + Tr + Th)
For Full-Revolution Clutch Machinery
Where the machine and its controls are designed to complete a full machine cycle,
once activated, use the following formula:
Ds = K x (Tm + Tr + Th)
For both formulas:
Ds = the separation distance in millimeters or inches,
K = 1600 mm (63") per second (the hand speed constant currently accepted by
OSHA; see NOTE 1)
Ts = the stop time (in seconds) of the machine, measured from the applica-
tion 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 (see NOTE 2)
Tr = 0.025 seconds (the response time of the Safety Module as measured from
the time either hand disengages a hand control)
Th = the response time of the slowest hand control (from the time when a hand
disengages that control until the switch opens; see NOTE 3)
Tm = the maximum time (in seconds) the machine takes to cease all motion
after it has been tripped. For full-revolution clutch presses with only one
engaging point, Tm is equal to the time necessary for 1.5 revolutions of the
crankshaft. For full-revolution clutch presses with more than one engaging
point, Tm is calculated as follows:
Tm = ( 1 /
2
+ 1 /
N
) x Tcy
where:
N = number of clutch engaging points per revolution
Tcy = time (in seconds) necessary to complete one revolution of the crankshaft
Electrical Installation
Because the DUO-TOUCH Safety Module interfaces to many types of machine controls,
it is not possible to give exact wiring instructions here. The following guidelines are
general in nature.
Connection of Input Switches
The actuation devices are connected to the DUO-TOUCH module as shown in Figures
5 a, b, and c. SW1 and SW2 must both be isolated normally-open switches capable of
reliably switching up to 20 mA, at 12V dc. If hand controls have metal housings, the
housings must be connected to protective earth ground.
If OTB Touch Buttons with PNP/NPN outputs are used, the System must be
connected as shown in Figure 5b. Electronic actuation devices other than OTB Touch
Buttons must share the same voltage supply with the Safety Module (see Electronic
Hand Control WARNING on page 7).
WARNING ...
Location of Touch
Button Controls
Hand controls must be mounted at a safe
distance from moving machine parts, as
determined by the appropriate standard.
It must not be possible for the operator
or other non-qualified persons to relocate
them. Failure to establish and maintain
the required safety distance could result in
serious injury or death.
!
Example Separation Distance (Ds)
Calculation
The following example illustrates the use of
the formula to calculate separation distance
for a part-revolution clutch machine. This
example uses 0.50 seconds as a typical
value for Ts and 0.10 seconds for Th:
K = 1600 mm (63") per second,
Ts = 0.50 seconds
(measured by a stop-time
measuring device)
Tr = 0.025 seconds
Th = 0.10 seconds
Ds = K x (Ts + Tr + Th)
= 1600 mm (or 63") (0.50 + 0.025 + 0.10)
= 1000 mm (39.4")
In this example, both hand controls must
be located no closer than 1000 mm (39.4")
from the nearest hazard point.
NOTES:
1) The OSHA-recommended hand speed
constant K has been determined by various
studies, and although these studies indicate
speeds of 1600-2500 mm/sec (63"/sec to
over 100"/sec), they are not conclusive deter-
minations. The employer should consider all
factors, including the physical ability of the
operator, when determining the value of K to
be used.
2) Ts is usually measured by a stop-time
measuring device. If the specified machine
stop time is used, add at least 20% as a
safety factor to account for brake system
deterioration. If the stop-time of the two
redundant machine control elements is
unequal, the slower of the two times must be
used for calculating the separation distance.
3) Th is usually insignificant for purely mechanical
switches. However, Th should be considered
for separation distance calculation when using
electronic or electromechanical (i.e., powered)
hand controls. In this example, OTB response
time = 0.10 seconds.