POWER-UP DIAGNOSTICS
Upon applying power, the LNXNT Timer performs an internal self-
diagnostic test of all the stored data. If the tests do not agree, a “P” appears on
the right side of the display. Normal operation of the unit will continue while
the “P” is displayed. Press the “E” button to remove the “P” and check all data
set-up values to be certain they are correct.
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 panel 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 extremely high EMI 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 (RLC #FCOR0000)
TDK # ZCAT3035-1330A
Steward #28B2029-0A0
Line Filters for input power cables:
Schaffner # FN610-1/07 (RLC #LFIL0000)
Schaffner # FN670-1.8/07
Corcom #1VB3
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.
6. Switching of inductive loads produces high EMI. Use of snubbers across
inductive loads suppresses EMI.
Snubbers:
RLC #SNUB0000
WIRING CONNECTIONS
When wiring the unit, use the numbers on the label to identify the position
number with the proper function. 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 (AC or DC) be protected by a fuse or circuit
breaker. Strip the wire, leaving approximately ¼" bare wire exposed
(stranded
wires should be tinned with solder)
. Insert the wire into the terminal and tighten
down the screw until the wire is clamped tightly. Each terminal can accept up
to one 14-gauge, two 18-gauge or four 20-gauge wire(
s
). Wire each terminal
block in this manner.
INPUT CONNECTIONS
Input connections are made on the terminal block at the rear of the unit, refer
to numbers on the label to identify the position number with the proper function.
Terminal 2
- “COMM.” (common) Is the common line to which the sensor and
other input commons are connected.
Terminal 3
- “RUN” When this terminal is connected to common, time will be
registered.
Terminal 6
- “PGM.DIS.” (program disable) When this terminal is left open
(unconnected), the following values can be programmed using the front panel
buttons:
Timed Output Values
Preset Values
Outputs can also be tested during self-test under this condition (See Self-Test
description for further details). When terminal is low (0.5 V
MAX
), changing
these values and testing the outputs is no longer possible.
Terminal 7
- “RMT.RST.” (remote reset) When low (0.5 V
MAX
) a manual reset
is performed. The outputs turn off
(if activated)
and the time display is reset.
As long as this terminal is low, the unit is held at reset.
POWER & OUTPUT CONNECTIONS
Power and output connections are made to the terminal block located at the
rear of the unit.
The DC power is connected to terminals 1 and 2. The DC plus (+) power is
connected to terminal 1 and the minus (-) is connected to terminal 2.
Terminals 4 & 5 are used to connect to the solid-state outputs. Terminal 2 is
used as common for the solid-state outputs. When switching an inductive load
with solid state outputs, it is recommended that an EMI device such as a snubber
(RLC #SNUB0000) be installed at the load.
Note: Snubber leakage current can cause some electro-mechanical devices to
be held on.
FRONT PANEL FUNCTION DESCRIPTION
These units employ eight front panel buttons for control and data entering.
The button functions are as described below:
RESET “R”
: Resets the timer to either zero or preset, depending on the mode
of operation selected. For this button to operate, the enable/disable reset DIP
switch at the rear of the unit must be set to the enable (EN.) position. The
reset button is also used in conjunction with the preset buttons, to view and
change the timed output values. When reset is activated, all processes are
stopped or interrupted (i.e. outputs turn off, display is reset). This is the case
under any mode of operation, in any data entry mode.
PRESET “P1” and “P2
”: The preset 1 value is displayed when the P1 button
is pressed, and the Preset Value mode is accessed (See Program Preset
Value). The value remains displayed for approximately 10 seconds after the
button is released.
The preset buttons are also used, in conjunction with the reset button, to view
and change the timed output values (See Program Timed Output Value.)
ENTER “E”
: The Enter button is used when programming the Preset Value or
the Timed Output Value. After the desired value is obtained on the display,
pressing the E button enters the value into the unit’s internal memory and
takes effect immediately. Also the “E” button can be used to exit self-test.
DISPLAY SCROLLING
To set the display to scroll, press and hold the “E” button and then press the
left-most button on the front panel. To stop the scrolling, repeat the above step.
DISPLAY SCROLLING SEQUENCE
P1
Value of P1
P2
Value of P2
Time Value
6
Courtesy of Steven Engineering, Inc.-230 Ryan Way, South San Francisco, CA 94080-6370-Main Office: (650) 588-9200-Outside Local Area: (800) 258-9200-www.stevenengineering.com
