Dynalco SW-100 Speed Switch - Manual (Page 4)

3
OVERVIEW
The SW-100 continuously monitors the input signal and controls an output
relay based on the frequency of the input signal, the chosen Operation Mode
(Underspeed or Overspeed), and the Trip and Release points the user has
selected. The green Input LED blinks at the rate of the input frequency. At about
100 Hz, the Input LED will appear to be solid on. At very low frequencies, the
Input LED blinks slowly and may also appear to be solid on. A loss of signal
may also cause the Input LED to remain on, depending on the DIP switch set-
up. In this case, the red Relay LED also turns on. The SW-100 indicates the
status of the relay with the Relay LED (Red). Whenever the relay is in the Trip
state, the SW-100 turns ON the Relay LED. In the Release state, the Relay LED
is OFF.
For Overspeed detection, when the input frequency (averaged over the
Minimum Response Time) exceeds the Trip point, the SW-100 trips the relay.
With the relay in the Trip condition, the input frequency must fall below the
Release point for the relay to release.
For Underspeed detection, the relay trips when the input frequency (averaged
over the Minimum Response Time) falls below the Trip point. The relay
releases only after the input frequency has exceeded the Release point. Two of
the Underspeed operating modes allow the machine or system that supplies the
input signal to reach normal operating speed before the SW-100 responds to an
Underspeed condition. For Zero Speed applications, bear in mind that Zero
Speed detection and Underspeed detection are identical.
The Minimum Response Time parameter sets the minimum update time of
the output. The actual response time is the Minimum Response Time plus up to
one full period of the input signal. The SW-100 counts the negative edges
occurring during the update time period, and computes the average frequency
value for that time. This action filters out any high frequency jitter that may be
present in the input signal. The longer the Minimum Response Time, the more
filtering occurs.
The Offset value is added to the Trip Frequency to determine the Trip Point
for Overspeed operation. For Underspeed operation the Trip point becomes the
Trip Frequency minus the Offset value.
If No Hysteresis has been selected, the Trip and Release points are identical,
which can lead to cycling or “chattering” of the relay at input frequencies
hovering around the Trip point. If Hysteresis is selected, the Release point is set
to the Trip point (including Offset) minus the Hysteresis value for Overspeed
detection. For Underspeed detection, the Release point is set to the Trip point
(including Offset) plus the Hysteresis value.
Two input pins (Alarm Override and Alarm Reset) are provided for the
optional connection of push-buttons. The Alarm Override pin causes the SW-
100 to unconditionally Release the relay, regardless of the input frequency, or
the state of the relay, when pulled to common. When the Alarm Override pin is
released from common, the operation of the SW-100 returns to normal, and the
status of the relay is updated based on the input frequency.
The Alarm Reset pin is only active when the SW-100 is in one of the Latch
operation modes. With the Latch function selected, the relay “latches” into the
Trip state whenever a Trip condition is detected. The relay remains latched until
the Alarm Reset pin is pulled to common while the input frequency is in the
Release region. The Alarm Reset pin is ignored while the input frequency is in
the Trip region.
EMC INSTALLATION GUIDELINES
Although this unit is designed with a high degree of immunity to
ElectroMagnetic Interference (EMI), proper installation and wiring methods must
be followed to ensure compatibility in each application. The type of the electrical
noise, source or coupling method into the unit may be different for various
installations. The unit becomes more immune to EMI with fewer I/O connections.
Cable length, routing, and shield termination are very important and can mean the
difference between a successful installation or a troublesome installation.
Listed below are some EMC guidelines for successful installation in an
industrial environment.
1. Use shielded (screened) cables for all Signal and Control inputs. The shield
(screen) pigtail connection should be made as short as possible. The
connection point for the shield depends somewhat upon the application.
Listed below are the recommended methods of connecting the shield, in
order of their effectiveness.
a. Connect the shield only at the rail where the unit is mounted to earth
ground (protective earth).
b. Connect the shield to earth ground at both ends of the cable, usually when
the noise source frequency is above 1 MHz.
c. Connect the shield to common of the unit and leave the other end of the
shield unconnected and insulated from earth ground.
2. Never run Signal or Control cables in the same conduit or raceway with AC
power lines, conductors feeding motors, solenoids, SCR controls, and
heaters, etc. The cables should be run in metal conduit that is properly
grounded. This is especially useful in applications where cable runs are long
and portable two-way radios are used in close proximity or if the installation
is near a commercial radio transmitter.
3. Signal or Control cables within an enclosure should be routed as far away as
possible from contactors, control relays, transformers, and other noisy
components.
4. In very electrically noisy environments, the use of external EMI suppression
devices, such as ferrite suppression cores, is effective. Install them on Signal
and Control cables as close to the unit as possible. Loop the cable through the
core several times or use multiple cores on each cable for additional protection.
Install line filters on the power input cable to the unit to suppress power line
interference. Install them near the power entry point of the enclosure. The
following EMI suppression devices (or equivalent) are recommended:
Ferrite Suppression Cores for signal and control cables:
Fair-Rite # 0443167251
TDK # ZCAT3035-1330A
Steward #28B2029-0A0
Line Filters for input power cables:
Schaffner # FN610-1/07
Schaffner # FN670-1.8/07
Corcom #1VR3
Note: Reference manufacturer’s instructions when installing a line filter.
5. Long cable runs are more susceptible to EMI pickup than short cable runs.
Therefore, keep cable runs as short as possible.
WIRING CONNECTIONS
All conductors should meet voltage and current ratings for each terminal.
Also cabling should conform to appropriate standards of good installation, local
codes and regulations. It is recommended that power supplied to the unit be
protected by a fuse or circuit breaker.
POWER AND OUTPUT CONNECTION
DC Power
The DC power is connected to
Terminals 10 and 12. The DC plus (+)
is connected to Terminal 10 and the
minus (-) is connected to Terminal 12.
It is recommended that separate
supplies be used for sensor power and
unit power. Using the same supply for
both will negate isolation between
input and power.
Output Wiring
Terminals 1, 2, and 3 are used to
connect to the relay output. Terminal 1
is the normally open contact. Terminal
3 is the normally closed contact, and
Terminal 2 is the output relay common.
1 2 3
4 6 5
7 9 8
10 12 11
OUT
IN
120/240
VAC
5 AMP 5 AMP
VAC
120/240
OVERRIDE
+12V
60mA
ALARM ALARM
RESET
INPUT
COMM
+
-