4-20 mA & Serial Data Output Transmitter for Time of Periodic Events

From from 1 µs to 199.999 s. Resolution to 0.2 µs. DIN Rail mounted, digitally programmable.

4-20 mA and Serial Data Output Transmitter for Time Average


  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V transmitter output, 16 bits, isolated
  • RS232 or RS485 serial data output, Modbus or TDM ASCII protocol, isolated
  • Dual 120 mA solid state relays for alarm or control, isolated
  • Transmits average time of periodic events with width from 1 µs to 199.999 s
  • Resolution to 0.2 µs, rep rated to 250 kHz
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic, or magnetic pickups down to 12 mV.
  • Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
  • 5V, 10V or 24V dc transducer excitation output, isolated
  • Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
Time Interval Mode for Time Delay

The time interval 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.

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.

Signal Conditioner Board for  Digital Time Interval Transmitter and Digital Timer

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.

Standard features of transmitters include:

  • 4-20 mA, 0-20 mA, 0-10V or -10V to +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 loops.
  • Serial communications output, RS232 or RS485 (half or full duplex), jumper selectable. Three protocols are user selectable: Modbus RTU, Modbus ASCII, or TDM ASCII. Modbus operation is fully compliant with Modbus Over Serial Line Specification V1.0 (2002). The TDM ASCII protocol is simpler than the Modbus protocol and is recommended when all devices are s.
  • Dual solid state relays, isolated, for alarm or control. Rated 120 mA at 140 Vac or 180 Vdc.
  • Transducer excitation output, isolated. User selectable 5V@100 mA, 10V@120 mA or 24V@50 mA.
  • Universal 85-264 Vac power. Low-voltage 10-48 Vdc or 12-32 Vac power is optional.

Easy Transmitter programming is via TDM'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 TDM (P/N CBL04).

Pulse Input
Types AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups
Signal Ground Common ground for channels A & B.
Minimum Signal Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V).
Maximum Signal 250 Vac
Maximum Frequency 1 MHz, 30 kHz, 250 Hz (selectable).
Contact Debounce 0, 3, 50 ms (selectable).
Time Base Accuracy Quartz crystal calibrated to ±2 ppm.
Span Tempco ±1 ppm/°C (typ)
Long-term Drift ±5 ppm/year
Time Interval Mode
Timing Start Channel A pulse, + or - edges
Timing Stop Channel B pulse, + or - edges
Update Rate Gate time + 30 ms + 0-2 time intervals
Gate Time Selectable 10 ms to 199.99 s
Time to Zero Output Selectable 10 ms to 199.99 s
0 - 199.999 s 1 ms
0 - 99.9999 s 100 µs
0 - 9.99999 s 10 µs
0 - .999999 s 1 µs
0 - .099999 s 0.2 µs (after averaging)
Analog Output (standard)
Output Levels 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable)
Compliance at 20 mA 10V (0-500Ω load)
Compliance at 10V 2 mA (5 kΩ or higher load)
Output Resolution 16 bits (65,536 steps)
Output Accuracy ±0.02% of output span
Output Update Rate Programmed gate time + 30 ms + 0-2 signal periods
Output Isolation 250V rms working, 2.3 kV rms per 1 minute test
Serial Data Output (standard)
Signal Types RS232 or RS485 (half or full duplex), jumper selectable
Data Rates 300, 600, 1200, 2400, 4800, 9600, 19200 baud
Output Isolation 250V rms working, 2.3 kV rms per 1 min test
Serial Protocols Modbus RTU, Modbus ASCII, TDM ASCII
Modbus Compliance Modbus over Serial Line Specification V1.0 (2002)
Ethernet Connector RJ45 jack for 10/100 Base-T Ethernet cable
RS232/485 Connector Screw terminals for easy daisy chaining
Digital Addresses 247 for Modbus, 31 for TDM ASCII
Dual Relay Output (standard)
Relay Type Two solid state relays, SPST, normally open, Form A
Load Rating 120 mA at 140 Vac or 180 Vdc
Transducer Excitation Output (standard)
Jumper Selection 1 10V @ 60 mA, isolated to 50V from signal ground
Jumper Selection 2 5V @ 50 mA, isolated to 50V from signal ground
Jumper Selection 3 15V @ 60 mA, non-isolated
Power Input
Standard Power 85-264 Vac or 90-300 Vdc
Low Power Option 10-48 Vdc or 12-32 Vac
Power Frequency DC or 47-63 Hz
Power Isolation 250V rms working, 2.3 kV rms per 1 min test
Power Consumption 2W typical, 3W with max excitation output
Dimensions 129 x 104 x 22.5 mm case
Mounting 35 mm rail per DIN EN 50022
Electrical Connections Plug-in screw-clamp connectors
Operating Temperature 0°C to 55°C
Storage Temperature -40°C to 85°C
Relative Humidity 95% at 40°C, non-condensing
Cooling Required Mount transmitters with ventilation holes at top and bottom. Leave 6 mm (1/4") between transmitters, or force air with a fan.
 LT transmitter pinout
Application Examples

Applications of Time Interval Meters & Transmitters

Time Interval Mode for Time Delay
Time Interval Mode for Time Delay For periodic pulses applied to A and B channels, time delays can be measured down to 0.2 µs resolution from the rising or falling edge of A to the rising or falling edge of B (selectable).
Time Interval Mode for Pulse Width
Time Interval Mode for Pulse Width The width of periodic pulses (t1 or t2) can be measured by tying the A and B channels together. As for time delay, readings are averaged over a user-selectable gate time.
Timing Process Dynamics with two Meters or Transmitters
Timing Process Dynamics with a Panel Meter and Time Interval Meter The start and stop pulses used for timing can be generated by the dual relay board in a panel meter, counter or transmitter. For instance, the start and stop pulse edges can be created as temperature passes two alarm setpoints, or temperature cycles in a hysteresis control mode.
Replacing an Oscilloscope with a Time Interval Meter or Transmitter
Replacing an Oscilloscope with a  Time Interval Meter 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 time interval meter or transmitter will be the instrument of choice. Resolution to 0.2 µs is feasible.
Instrumenting a Pulsed Laser System
Instrumenting a laser system using  timers and stopwatches Some of the many possibilities in instrumenting a pulsed laser system with dual-channel counters and transmitters: elapsed time, number of pulses, pulse width, pulse separation, duty cycle, and pulse rep rate.

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