4-20 mA & Serial Data Output Transmitter for Process & Ratio Signals

Scalable for process signals requiring zero and span adjustment. Ideal for pressure & flow. DIN Rail mounted, digitally programmable.

Process Transmitter with 4-20 mA and Modbus Output

Features

  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V transmitter output, 16 bits, isolated
  • Ratiometric mode for bridges and potentiometers
  • RS232 or RS485 serial data output, Modbus or TDM ASCII protocol, isolated
  • Dual 120 mA solid state relays for alarm or control, isolated
  • 200 mV, 2V, 20V, 200V, 300V & 600V DC voltage input ranges
  • 2, 20, 200 mA and 5A DC current input ranges
  • All ranges factory calibrated
  • Digital span adjust from 0 to ±99,999, zero adjust from -99,999 to +99,999
  • 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
Description

The 4-20 mA and RS232/RS485 output, process signal input transmitter provides zero and span adjustment for use with a wide range of industrial transducers. Six DC voltage and four DC current input ranges are jumper selectable. The two most sensitive voltage ranges, 200.00 mV and 2.0000V, provide a high input impedance of 1 GΩ to minimize the load on the voltage signal.

The transmitter can be set to a ratio mode (or potentiometer follower mode) by making selections at the connector and in software. In this mode, the transmitter output tracks a ratio of the applied excitation voltage and is unaffected by changes in the excitation voltage. This capability is used for resistive bridge sensors and voltage dividers, such as potentiometers which track wiper position. Ratiometric measurements provide an exceptional accuracy of 0.01% of reading ± 2 counts.

Fast read rates at up to 50 or 60 conversions per second while integrating the signal over a full power line cycle are ideal for peak or valley capture and for real-time computer interface and control. Digital signal filtering modes are selectable for stable readings in electrically noisy environments. The internal digital readings and analog output can be individually selected to be either unfiltered or filtered.

Standard features of LT transmitters include:

  • 4-20 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 loop problems.
  • 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).

Specifications
Analog Input Range Resolution Reading Accuracy Input Ohms
DC Voltage ±200.00 mV 10 µV 0.01% FS ± 2 cts 1 GΩ
±2.0000 V 100 µV 0.01% FS ± 2 cts 1 GΩ
±20.000 V 1 mV 0.01% FS ± 2 cts 10 MΩ
±200.00 V 10 mV 0.01% FS ± 2 cts 10 MΩ
±600.0 V* 100 mV ± 0.4 V 10 MΩ
DC Current ±2.0000 mA 0.1 µA 0.01% FS ± 2 cts 100 Ω
±20.000 mA 1 µA 0.01% FS ± 2 cts 10 Ω
±200.00 mA 10 µA 0.01% FS ± 2 cts 1 Ω
±5.000 A 1 mA ±10 mA 0.01 Ω
* Range not ETL certified.
Reading Resolution 16 bits (65,536 steps)
Reading Accuracy 0.01% of full scale ± 2 counts (except 5A range) for absolute measurements.
0.01% of reading ± 2 counts for ratiometric measurements.
Update Rate, Max 50/sec at 50 Hz, 60/sec at 60 Hz
Max applied voltage 600 Vac for 20, 200 & 600 V ranges, 125 Vac other ranges
Over-current protection 25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5 A
Analog Output (standard)
Output Levels 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable)
Compliance, 4-20 mA 10V (0-500Ω load)
Compliance, 0-10V 2 mA (5 kΩ load)
Output Resolution 16 bits (65,536 steps)
Output Accuracy 0.02% of output span plus conversion accuracy
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 TCP, 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/RS485 Screw terminal connector 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)
Output Levels 5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable)
Output Isolation 50V from signal ground
Ratiometric operation Selectable at connector and in software
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
Mechanical
Dimensions 129 x 104 x 22.5 mm case
Mounting 35 mm rail per DIN EN 50022
Electrical Connections Plug-in screw-clamp connectors
Environmental
Operating Temp. 0°C to 55°C
Storage Temp. -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.
Pinout

Ethernet & 4-20 mA Output Transmitter for Process & Ratio Signals

 LT transmitter pinout

Custom curve linearization

Using a linearizing digital panel meter or transmitter

A process meter or transmitter with the Extended main board option allows exceptionally accurate custom curve linearization. For setup, up to 180 data points can be entered into a spreadsheet. The system then creates multiple non-linear spline-fit segments, which provide much better accuracy than linear segments. One application, as illustrated, is the readout of volume of irregularly shaped tanks based on measured liquid level or pressure. Altimeters and thermistors are further applications.

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