Modbus & Serial Output Transmitter for Time of Single or Accumulated Events

• 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.
• 0-10V, 4-20 mA or 0-20 mA analog output, scalable, isolated
• Universal AC power, 85-264 Vac
• Priced at only $235 (basic stopwatch transmitter)

• Low voltage power, 10-48 Vdc or 12-32 Vac

The Laureate Modbus & serial output stopwatch transmittertransmits the time of single events which produce start and stop pulses, or accumulated time of multiple events. It can also time the width of a single pulse. The highest resolution is 0.2 µs, making the transmitter 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 Laureate transmitters include:

• Serial communications, isolated. User selectable RS232 or RS485, half or full duplex, Modbus or Laurel ASCII protocol.
• Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA, 0-20 mA or 0-10V levels.
• 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).