Product Description
T752 Two-Wire Transmitter
The T752 Two-Wire Transmitter accepts potentiometer inputs from 0 to 50 Ohms to 0 to 200k Ohms (end to end). The T752 provides 600 VDC of isolation with outputs of either 4-20mA or 10-50mA which are field selectable via top accessed DIP switch. The current outputs are in proportion to the potentiometer input. Urethane coating of internal circuitry for protection from corrosive atmospheres is included as standard.
The T752 has 80% zero and span adjustability within the input range of the potentiometer. This allows the user to field calibrate the unit for a wide variety of input spans from the maximum (100%) down to any minimum (20%) span (e.g., 4% to 24%) as long as the adjusted span remains within the input range of the potentiometer.
Application
The T752 is useful in any application requiring isolation of a 2-wire loop current from a 3-wire potentiometer. Typical applications include tank level data acquisition and position sensor conditioning. The output of the T752 can be used to drive a digital meter for direct display or interface with a computer for monitoring or control.
The T752 is FM approved for intrinsically safe operation in Class I, Division 1, Groups A, B, C, and D; Nonincendive Class I Division 2, Groups A, B, C and D, and Classes II & III, Division 2, Group G hazardous locations when installed per manufacturer’s drawing 790-0024-00.
Calibration
| Input Range: | 0-100% |
| Output Range: | 4-20mA |
- Open the access lid on the top of the unit (see Top View Diagram).
- Select the output range using switch 1. The CLOSED position selects a 10-50mA output. The OPEN position selects a 4-20mA output. (Switches 2-6 are not used.)
- Connect the input to a potentiometer. Connect the output loop to a voltage supply and monitor the output current (refer to the terminal wiring).
- Set the potentiometer to the desired minimum.
- Adjust the coarse zero rotary switch to obtain an output of either 4mA or 10mA. Adjust the fine zero for exact calibration. Note that it may be necessary to switch the coarse zero up or down one position.
- Set the potentiometer to the desired maximum and perform similar adjustments using the coarse and fine span potentiometer.
It may be necessary to repeat steps 4, 5, and 6 for best accuracy.
Field Mounting
The T752 is designed for installation in industrial field environments. A sealed, diecast aluminum housing protects against corrosion, moisture, dust and electrical noise such as radio-frequency (RFI) and electromagnetic (EMI) interference. All circuit boards are urethane coated for environmental protection and FM approval.
For protection against extreme moisture, hosedirected water (NEMA 4) or hazardous environments, use Action’s T805 explosion-proof housing. The T805 provides a 1/2″ and 3/4″ FPT port for easy hook-up and operation in harsh process environments. Model T805 is FM and CSA certified for use in Class I, Groups B, C & D and Class II, Groups E, F & G hazardous locations.
TECHNICAL SPECIFICATION (T752)
Input Span Range
- Max: 0 to 100% of potentiometer
- Min: 0 to 20% of potentiometer
Excitation Voltage
50mV typical
Potentiometer Resistance (End to End) 50 Ohms to 200k Ohms
Leadwire Resistance Effect
<0.25 uV/Ohm
Input Impedance
5M Ohms, typical
Output Span
4-20mA or 10-50mA, switch selectable
Minimum Output Current
3.3mA typical
Maximum Output Current
- 4-20mA: 24mA typical
- 10-50mA: 58mA typical
Supply-Voltage Range
- 4-20mA: 12 to 80VDC
- 10-50mA: 12 to 60VDC
Maximum Change in Supply Voltage Effect
0.05% of span
Maximum Change in Load Effect
0.05% of span
Loop Voltage Drop
12VDC @ 20mA
Stability
- Zero: ±0.02% of span/°C typical, or 2uV, whichever is greater
- Span: ±0.01% of span/°C typical
Overall Accuracy (Includes Linearity,Hysteresis, Repeatability)
±0.05% of any adjusted span maximum
Zero and Span Adjustability
80% of input
Repeatability
±0.05% of span
Response Time
50ms, max.
Output Ripple
0.1% of span rms, typical
RFI Effect (5W, 470MHz at 3 Ft.)
<1% of span error
Isolation
600V DC maximum, input to output to case
Temperature Range
Operating: -40 to 80°C (-40 to 176F)
Weight
0.62lbs
Agency Approval
FM approved intrinsically safe for hazardous location, certificate No. J.I. 2M2A5.AX.
