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Description
Time interval is measured between inputs on channels A and B. Timing starts when a pulse is applied to Channel A (selectable positive or negative edge), and ends when a pulse is applied to Channel B (selectable positive or negative edge). In case of a single pulsed signal, the A and B inputs can be tied together. A positive or negative slope may be selected to start timing, and the opposite slope must be selected to stop timing. Timing is achieved by counting 5.5 MHz clock pulses. Multiple integral time intervals are averaged over a gate time which is selectable from 10 ms to 199.99 s and also controls the maximum output rate.
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 Micron ASCII. Modbus operation is fully compliant with Modbus Over Serial Line Specification V1.0 (2002). The Micron ASCII protocol allows up to 31 Micron devices to be addressed on the same RS485 data line. It is simpler than the Modbus protocol and is recommended when all devices are Microns. It also allows use of Micron Datalogging Software. Standard features of Micron transmitters include:
Easy Transmitter programming is via Micron'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 Micron (P/N CBL04). |
Pulse Input |
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Types 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 (typ) ±5 ppm/year |
Time Interval Mode |
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Timing Start Timing Stop Periodic Timing Interval Gate Time Time Before Zero Output |
Channel A pulse, + or - edges Channel B pulse, + or - edges Gate time + 30 ms + 0-2 time intervals Selectable 10 ms to 199.99 s Selectable 10 ms to 199.99 s |
Resolution |
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0 - 199.999 s 0 - 99.9999 s 0 - 9.99999 s 0 - .999999 s 0 - .099999 s |
1 ms 100 µs 10 µs 1 µs 0.2 µs (after averaging) |
Serial Data Output (standard) |
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Signal levels Data Rates Output Isolation Serial Protocols Devices on RS48 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, Micron 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) |
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Output levels Output isolation |
5V@100 mA, 10 @120 mA, 24V@50 mA (jumper selectable) 50V from signal ground |
Dual Relay Output (standard) |
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Relay Type Load rating |
Two solid state relays, SPST, normally open, Form A 130 mA at 140 Vac or 180 Vdc |
Analog Output (standard) |
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Output Levels Compliance, 4-20 mA Compliance, 0-10V Output Resolution Output Accuracy Output Isolation |
4-20 mA, 0-20 mA, 0-10 Vdc (jumper selectable) 10V ( 0-500 ohm load ) 2 mA ( 5 kOhm load or higher) 16 bits (65,536 steps) 0.02% of output span 250V rms working, 2.3 kV rms per 1 minute test |
Power Input |
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Standard power Low power option Power frequency Power isolation Power consumption |
85-264 Vac or 90-300 Vdc (DC operation not UL approved) 10-48 Vdc or 12-30 Vac DC or 47-63 Hz 250V rms working, 2.3 kV rms per 1 min test 2W typical, 3W with max excitation output |
Mechanical |
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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 |
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Operating Temperature Storage Temperature Relative Humidity Protection Cooling Required |
0°C to 55°C -40°C to 85°C 95% at 40°C, non-condensing NEMA-4X (IP-65) when panel mounted Mount transmitters so that ventilation holes are at top and bottom. Leave 6 mm (1/4") between transmitters, or blow air by means of a fan. |
| Instrumenting a Pulsed Laser System |
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The Micron Modbus & serial output, time interval input transmitter can transmit pulse width or time delay between individual pulses to a resolution of 0.2 µs for periodic events. It can also transmit average pulse width or average time delay between multiple pulses. 
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. 
