LTM-ST
Modbus & Serial Output Transmitter
for
Time of Single
or Accumulated Events Resolution to 0.2 µs.
Duration to 999,999 hrs.
DIN Rail mounted, digitally
programmable.
Standard Features
Selectable Modbus or Laurel ASCII
protocol.
Modbus
RTU or ASCII modes, 2-wire connection,
up to 247 digital addresses.
Times single event time or accumulated
time of all events.
Timing
resolution to
0.2 µs.
Timing duration to 999,999 hrs.
Selectable H, M or S decimal format.
Selectable HH.MM.SS clock format.
Inputs from NPN or PNP proximity
switches, contact closures, digital
logic, or magnetic pickups down to 12
mV.
5V, 10V or 24V dc sensor excitation
output, isolated.
Dual solid state relays for alarm or control,
isolated.
0-10V, 4-20 mA or 0-20 mA analog output,
scalable, isolated.
Universal AC power, 95-240 Vac ±10%
Priced at only $235
(basic stopwatch transmitter)
Options:
Low voltage
power, 10-48 Vdc or 12-30 Vac.
Description
The
Laureate LTM-ST
4-20 mA stopwatch
transmitter puts out an analog signal whose whose value tracks the
time of single events which produce start and stop pulses, or accumulated
time of multiple events. They can also time the width of a single pulse.
The highest resolution is 0.2 µs, making the transmitters ideal for fast
events. The longest timing interval is 999,999 hrs. For long events, the
analog output
is updated continuously during timing. There are two primary timing modes:
A-A Stopwatch Mode.
Time is measured between a start pulse and a
stop pulse, both on Channel A, from either the positive or negative edges.
A-B Stopwatch Mode.
Time
is measured between a start pulse on Channel A (positive or negative edge) and a
stop pulse on Channel B (positive or negative edge). This mode allows inputs from
different sources. In addition, the A and B inputs can be tied together to start the stopwatch with one polarity and stop it with the other
polarity.
Event time (Item #1)
is measured by counting 5.5 MHz
clock pulses from a calibrated quartz crystal.
The stopwatch
output is updated during timing
at a rate controlled by a gate time, up to 25/sec. Time is reset to zero when the next start
pulse occurs. Accumulated time from multiple events up to 999,999 hours (Item #2)
can also be tracked.
The dual-channel signal
conditioner used for pulse detection accepts inputs from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures, and other signals from
12 mV to 250 Vac. Jumper
selections provide optimum operation for different sensor types and noise
conditions. A built-in 5V, 10V or 24V dc
excitation supply can power proximity switches and other sensors, and eliminate the need
for an external power supply.
LTM Series serial
output transmitters send data via an isolated serial port, which is user
configurable for RS232 or RS485 and full or half duplex operation. Three
protocols are user selectable: Modbus RTU, Modbus ASCII, or Laurel ASCII. Modbus operation
is fully compliant with Modbus Over Serial Line Specification V1.0 (2002).
The Laurel ASCII
protocol allows up to 31 Laureate devices to be addressed on the
same RS485 data line. It is simpler than the Modbus protocol and is
recommended when all devices are Laureates. It also allows use of
Laurel Datalogging Software.
Standard features of Model
LTM-ST include:
Serial data output, isolated. User selectable RS232 or RS485, half or full duplex, Modbus or
Laurel ASCII protocol.
Dual solid state relays for control or alarm, isolated.
Rated 120 mA at 130 Vac or 170 Vdc.
Transducer excitation output, isolated. User selectable 5V@100 mA, 10V@120 mA or 24V@50
mA.
Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA,
0-20 mA or 0-10V levels.
Universal AC power supply for 95-240 Vac ±10%.
Easy Transmitter programming is via
Laurel's Instrument Setup Software,
which runs on a PC under MS Windows. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from
Laurel (P/N CBL04).
Specifications
LTM-ST Modbus & Serial I/O
Transmitter
for Time of Single or Accumulated Events
Pulse Input
Signal Sources
Ch A Frequency, Max
Ch B Frequency, Max
Signal Ground
Minimum Signal
Maximum Signal
Maximum Frequency
Contact Debounce
Time Base Accuracy
Span Tempco
Long-term Drift
AC, pulses from
NPN, PNP transistors, contact closures,
magnetic pickups.
1 MHz.
250 kHz.
Common ground for channels A & B.
Nine ranges from (-12 to +12 mV) to (+1.25
to +2.1V).
250 Vac
1 MHz, 30 kHz, 250 Hz (selectable).
0, 3, 50 ms (selectable).
Quartz crystal calibrated to ±2 ppm.
±1 ppm/°C (typical)
±5 ppm/year
Stopwatch
Operation
Timing Modes:
With CH A only
With CH A tied to CH B
With CH A and CH B
Timing Interval
Timing Resolution
Selectable Decimal Time
Selectable Clock Time
Output Update
Gate Time
+ to + edge, or - to - edge.
+ to - edge, or - to + edge.
+ edge of A to + edge of B, + edge of A to -
edge of B,
- edge to A to - edge of B, - edge of A to -
edge of B
1 µs to 999,999 hrs
0.2 µs to 1 hr
999999 H, M or S format with decimal point
HH.MM.SS format
Gate time + 30 ms
Programmable from 10 ms to 199.99 s
Serial Data Output
(standard)
Signal levels
Data Rates
Output Isolation
Serial Protocols
Devices on RS-485 Line
Modbus Addresses
Modbus Modes
Modbus Compliance
RS232 or RS485 (half duplex)
300, 600, 1200, 2400, 4800, 9600, 19200 baud
250V rms working, 2.3 kV rms per 1 min test
Modbus RTU, Modbus ASCII, Laurel ASCII (selectable)
32 max without a repeater.
247 max
RTU or ASCII, 2-wire.
Modbus over Serial Line Specification V1.0 (2002).
Transducer Excitation Output (standard)
Output levels
Output isolation
5V@100 mA, 10 @120 mA, 24V@50 mA (jumper
selectable)
50V from signal ground
Dual Relay Output (standard)
Relay Type
Load rating
Two solid state relays, SPST, normally open,
Form A
120 mA at 130 Vac or 170 Vdc, 28 ohms in series
4-20 mA, 0-20 mA, 0-10 Vdc (jumper selectable)
10V ( 0-500 ohm load )
2 mA ( 5 kOhm load or higher)
16 bit DAC
±0.02% of output span plus conversion accuracy
250V rms working, 2.3 kV rms per 1 minute test
Power Input
Standard power
Low power option
Frequency
Power Isolation
95-240 Vac ±10% or 90-300 Vdc (DC operation not UL approved)
12-30 Vac or 10-48 Vdc
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
Mechanical
Case Dimensions
Case Mounting
Electrical Connections
120 x 101 x 22.5
mm
35 mm rail per DIN EN 50022
Detachable screw clamp plug connectors
Environmental
Operating
Temperature
Storage Temperature
Relative Humidity
0°C to 70°C
-40°C to 85°C
95% at 40°C, non-condensing
Application Examples of
Stopwatch Meters
Stopwatch Mode
The
stopwatch mode is used to time single events
between start and stop pulses on the same
channel. Duration of a single wave shape can
be measured by tying the A and B channels
together.
Timing Process Dynamics
The start
and stop pulses used for timing can be
generated by the dual relays in a Laureate
panel meter, counter, or transmitter. For
instance, the start and stop pulse edges can
be created as temperature passes two alarm
setpoints, or as temperature cycles in a
hysteresis control mode.
Replacing an Oscilloscope with a
Laureate Meter or Transmitter
An
oscilloscope is great for viewing and timing
pulses in a lab. However, in fixed
installations where digital timing accuracy
and control outputs are required, a low-cost
Laureate time interval meter or transmitter
will be the instrument of choice. Resolution
to 0.2 µs is feasible.
Instrumenting a Pulsed Laser System
Some
of the many possibilities in
instrumenting a pulsed laser system
with Laureate dual-channel counters
and transmitters: elapsed time,
number of pulses, pulse width, pulse
separation, duty cycle, and pulse
rep rate.
Pinout
LTM-ST Modbus & Serial I/O
Transmitter
for Time of Single or Accumulated Events
Ordering
Guidee
LTM-ST Modbus & Serial I/O
Transmitter
for Time of Single or Accumulated Events Click
on the radio buttons to build a model number with pricing.
The
Laureate LTM-ST
4-20 mA stopwatch
transmitter puts out an analog signal whose whose value tracks the
time of single events which produce start and stop pulses, or accumulated
time of multiple events. They can also time the width of a single pulse.
The highest resolution is 0.2 µs, making the transmitters ideal for fast
events. The longest timing interval is 999,999 hrs. For long events, the
analog output
is updated continuously during timing. There are two primary timing modes:
The dual-channel signal
conditioner used for pulse detection accepts inputs from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures, and other signals from
12 mV to 250 Vac. Jumper
selections provide optimum operation for different sensor types and noise
conditions. A built-in 5V, 10V or 24V dc
excitation supply can power proximity switches and other sensors, and eliminate the need
for an external power supply.
