Nexen RSD100 964520 - Manual (Page 20)

FORM NO. L-21107-H-0108 0
The MINIMUM and MAXIMUM OUTPUT settings override all other settings and allow the RSD100 OUTPUT to
be limited. Generally the MINIMUM and MAXIMUM will be set at 0 and 100% respectively. However, in some
applications these values may need to be adjusted.
example One: Air supply pressure exceeds the maximum air pressure rating of a brake or clutch. For instance, an I/P
transducer can supply 125 psi to a brake rated for 80 psi. The MAXIMUM OUTPUT % should be set as follows:
MAXIMUM OUTPUT % = (maximum brake pressure / supply air pressure) * 100 = (80 / 125)*100 = 64%
example Two: A pneumatic brake or clutch that is spring disengaged; In this case the MINIMUM OUTPUT % would
be set high enough to overcome the spring and allow the friction facing to just contact the rotor.
.0 OUTPUT LIMITS
.0 STOPPeD SeTTINGS
u
nwinD
A
pplicAtiOnS
Without any brake pressure, the force on the dancer arm can spin the roll. In addition, out-of-round rolls can rotate
by themselves until their heavy side is at the lowest point. Consequently, in most unwind applications it is important
to provide some brake pressure while the machine is stopped to prevent the roll from turning. The RSD100 not only
allows for a configurable STOPPED OUTPUT%, it will ramp to this value after a machine stop thereby minimizing
dancer arm disturbances.
w
inDing
A
pplicAtiOnS
Without any output, the force on the dancer arm or an out-of-round roll could cause the roll to spin backwards and
spill web onto the floor. With the RSD100 there are two ways to prevent this from happening. First, leave the RSD100
in run mode even while the machine is stopped in order for the arm position to be maintained. Or, use the Stopped
Output feature to provide a minimal level of output to keep tension on the web.
STOPPeD bLeeD RaTe
STOPPED BLEED RATE controls the rate at which the output is ramped to the STOPPED OUTPUT value after the
machine stops (machine state signal is low). If this value is increased, the RSD100 OUTPUT will ramp faster to the
STOPPED OUTPUT value. Set this value so the dancer arm does not move quickly to the maximum web loop position
after a machine stop. If STOPPED BLEED RATE is set too fast, the force on the dancer arm will spin the roll and
slacken the web. If STOPPED BLEED RATE is set too slow, the ramp may not finish before another machine start
occurs.
STOPPeD OUTPUT
Set STOPPED OUTPUT to the maximum OUTPUT % level the web can handle during a start at core and minimum
tension (on variable tension machines). If STOPPED OUTPUT is set too high, when the machine accelerates from a
stop at core, the dancer web loop will be consumed very quickly and cause a tension spike when the dancer arm hits
an end-of-travel stop.
NOTe: Use the PROPORTIONaL MULTIPLIeR (STaRT SeTTINGS section) to bring the output up quickly for
full roll starts. Setting the STOPPeD OUTPUT too high can cause excessive tension in the web and the dancer
arm to hit an end-of-travel stop during starts near core.