Laurel Electronics LT: 4-20 mA & Serial Data Output Transmitter for AC RMS Voltage or Current Input - Manual

LAUREL ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 1
LAUREL
ELECTRONICS, INC.
4-20 mA & Serial Data Output Transmitter
for AC RMS Voltage or Current Input
Features
• True AC RMS measurement in one 50/60 Hz AC line cycle
• 0.2, 2, 20, 200, 300V and 600V AC voltage ranges
• 2, 20, 200 mA and 5A AC current ranges
• All input ranges user-selectable and factory calibrated
• AC or DC coupling for signals from DC to 10 kHz
• 0.1% accuracy of full scale, 0% to 100% of full scale
• Crest factor of 3.0 at full scale
• 4-20 mA or 0-10V transmitter output, jumper selectable, isolated
• Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
• RS232 or RS485 serial data output, half or full duplex, isolated
• Modbus RTU, Modbus ASCII or Laurel ASCII protocol
• Dual solid state relays for alarm or control, isolated
• Universal AC power, 85-264 Vac, or low voltage power, 10-48 Vdc or 12-32 Vac
• Custom curve linearization and rate from successive readings (optional)
Description
The Laureate 4-20 mA output, AC RMS input transmitter
provides six voltage input ranges and four current input ranges,
all factory calibrated and jumper selectable. A special 5.000A
range utilizes a built-in 0.01Ω shunt to accept the output of 5A
current transformers, with no need for a stepdown transformer.
The current readings can easily be scaled digitally as needed.
True RMS precision circuitry is used to determine the root-
mean-square of complex waveforms from DC to 10 kHz. Spikes
up to 3.0 times the maximum of each range are accurately
measured.
Accuracy is 0.1% of full scale* for signals from DC to 10 kHz
and signal amplitude down to 0. The crest factor (Vp / Vrms) is
3.0 at full scale, increasing to 300 for a signal amplitude of 1% of
full scale.
True RMS readings in as little as one 50/60 Hz AC line cycle
are unmatched in the industry. Such a high read rate allows
anomalies to be detected and alarmed before they become
expensive problems. On/off control and alarm can be achieved
dual solid state relays, which are standard. Transmitter can also
capture peak and valley for times as short as one 50/60 Hz AC
power line cycle.
AC or DC coupling is jumper selectable. AC coupling accom-
modates signals from 10 Hz to 10 kHz for applications such as
measuring the ripple on a DC power supply. DC coupling accom-
modates signals from 0 Hz to 10 kHz. Multiple integral cycles are
averaged for signals above 50/60 Hz. A single cycle is captured
for signals from 3 Hz to 50/60 Hz. Below 3 Hz and at DC, the
capture rate is every 333 ms.
Standard features of Laureate LT transmitters include:
• 4-20 mA, 0-20 mA or 0-10V analog transmitter output,
isolated, jumper-selectable and user scalable. All selections
provide 16-bit (0.0015%) resolution of output span and 0.02%
output accuracy of a reading from -99,999 to +99,999 counts
that is also transmitted digitally. Output isolation from signal
and power grounds eliminates potential ground loop problems.
The supply can drive 20 mA into a 500Ω (or lower) load for
10V compliance, or 10V into a 5 kΩ (or higher) load for 2 mA
compliance.
• Serial communications output, isolated. User selectable
RS232 or RS485, half or full duplex. 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.
• Dual solid state relays, isolated. Available for local alarm or
control. Rated 120 mA at 130 Vac or 170 Vdc.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or
12-32 Vac power is optional.
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).