Modbus & Serial Output Transmitter for Duty Cycle Input

Transmits ON or OFF period in percent of total period. DIN Rail mounted, digitally programmable.
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Serial ASCII or Modbus Transmitter, Duty Cycle Input
Key Features
  • Selectable Modbus or Laurel ASCII protocol
  • Modbus RTU or ASCII modes, 2-wire connection, up to 247 digital addresses
  • Transmits ON or OFF period as a percentage of total period
  • Resolution of 1%, 0.1% or 0.01%
  • Frequencies from .005 Hz to 10 kHz
  • Triggers on positive or negative pulse edges
  • Optional dual solid state relays for alarm or control
  • 5V, 10V or 24V dc sensor excitation output, isolated
  • Dual solid state relays for alarm or control, isolated
  • Dual solid state relays for alarm or control, isolated
  • 0-10V, 4-20 mA or 0-20 mA transmitter output, isolated
  • Universal AC power, 85-264 Vac
Standard Features
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC inputs up to 250 Vac.
  • DIN rail mount housing only 22.5 mm wide
  • Plug-in screw-clamp connectors
  • Easy setup with PC-based Instrument Setup Software
  • Priced at only $275 (basic pulse input transmitter)
Options
  • Low voltage power, 10-48 Vdc or 12-32 Vac
Description

The Laureate Modbus & serial output, duty cycle input transmitter tracks ON or OFF period as a percentage from 0% to 100% of total period of repetitive pulse trains. In the illustration, duty cycle is 100 x t/P. The transmitter determines duty cycle by averaging an integral number of periods over a gate time, which is selectable from 10 ms to 199.99 s. The same signal is applied to Channels A and B. The unit divides the average pulse width by the period between pulses and expresses this ratio in percent. A resolution of 1%, 0.1% or 0.01% is selectable. By selecting leading or falling pulse edges, the ON or OFF duty cycle can be transmitted.

 Clock diagram, 4-20 mA duty cycle transmitter

The dual-channel signal conditioner ccepts inputs from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures, and AC signals from 12 mV to 250 Vac. Jumper selections provide optimum operation for different sensor types and noise conditions.

 Signal conditioner board, 4-20 mA duty cycle transmitter

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 Laureate transmitters include:

  • Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA, 0-20 mA or 0-10V levels.
  • Serial communications, 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.
  • Universal AC power supply for 85-264 Vac.
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).