Product Description
T773 Two-Wire Transmitter
The T773 Two-Wire Transmitter isolating two-wire transmitter has 5 input ranges and 2 output ranges, all of which are field selectable via top-accessed DIP switches. The T773 can accept square, triangle or pulse waveforms up to 18KHz with amplitudes from 10mVrms to 35V peak-to-peak. The T773 provides 1000Vrms of transformer-coupled isolation with outputs of either 4-20mA or 10-50mA. Current outputs are in proportion to a selected frequency input.
The T773 has 30% zero “turn-up” and 80% span “turn-down” adjustments within any user-selected input range. For example, Range 3 of Table 1 specifies 0 to 2100Hz with a minimum span of 420Hz (2100Hz – 420Hz = 1680Hz, or 80%). This 80% adjustability allows the user to field calibrate the unit for the maximum range of 0 to 2100Hz down to the minimum range of 0 to 420Hz. The maximum obtainable offset is 30% of the calibrated span: a calibrated range of 0 of 1000 Hz can be offset by 300Hz (e.g., 300Hz to 1000Hz).
Application
The T773 is useful in any application requiring isolation of a 2-wire loop current from a pulse output transducer, such as a magnetic pickup or a turbine flowmeter. The output of the T773 can be used to drive a digital meter for direct display of flow or velocity, or to interface with a computer or PLC for monitoring and control applications.
The T773 is CSA approved for intrinsically safe operation in Class I, Division 1, Groups A, B, C and D hazardous locations when installed per manufacturing drawing number.
Calibration
| Input Range: | 1 |
| Output Range: | 4-20mA |
- Open the access lid on the top of the unit (see Top View Diagram).
- Select the output range using switch S6. The CLOSED position selects a 10-50mA output. The OPEN position selects a 4-20mA output.
- Select the input range from Table 1 and configure switches S1 through S5.
- Determine the percent of span by the ratio of the desired maximum input to the input limit in Table 1 (e.g., 1000Hz/2100Hz = 48%).
- Set the step Span rotary switch to the desired percent of span (e.g., 48% = position 4).
| Percent of Span | Position |
| 100% | A |
| >90% | 9 |
| >80% | 8 |
| >70% | 7 |
| >60% | 6 |
| >50% | 5 |
| >40% | 4 |
| >30% | 3 |
| >20% | 2 |
- Determine Zero turn-up % by the ratio of desired minimum input to the desired maximum input (e.g., 0/1000Hz = 0%).
- Set step Zero turn-up switch to offset %. (e.g., 0% = position 0).
| Zero Turn-Up % | Position |
| 0% | 0 |
| >10% | 1 |
| >20% | 2 |
| >30% | 3 |
- Connect the input to a calibrated frequency source. Connect the output loop to a voltage supply and monitor the output current (refer to the terminal wiring).
- Set the calibrator to the desired minimum and adjust the fine zero to obtain an output of either 4mA or 10mA.
- Set the calibrator to the desired maximum and adjust the fine span to obtain an output of either 20mA or 50mA. Repeat steps 9 and 10, if necessary, for maximum accuracy.
Note: If loop current “swings” on input ranges 1-2, close S-5 for extra filtering.
Field Mounting
The T773 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.
For protection against extreme moisture, hosedirected water (NEMA 4) or hazardous environments, use the T805 explosion-proof housing. The T805 provides a 1/2″ and 3/4″ FPT port for operation in harsh process environments. The 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 (T773)
Input
- Type: Capacitive coupled
- Minimum Amplitude:
- 105-2150Hz: 10mVrms
- >2150Hz: 15mVrms
- Maximum Amplitude: 35Vp-p
Impedance
- 100-1KHz: >6k Ohms
- >1KHz: >40k Ohms
Output Span
4-20mA/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: 13 to 75VDC
- 10-50mA: 13 to 50VDC
Line Regulation
0.07% of span (13-75V)
Load Regulation
0.05% of span (0-3k Ohms)
Voltage Drop
13VDC @ 20mA
Stability
- Zero: ±0.015% of span/°C, typical,
±0.028%/°C, max. - Span: ±0.022% of span/°C, typical,
±0.043%/°C, max.
Overall Accuracy (Includes Linearity, Hysteresis, Stability)
±0.2% of adjusted span, max.
Zero Adjustability
30% “turn-up” of span
Span Adjustability
80% “turn-down” of full-scale limit (Table 1)
Repeatability
±0.05% of span
Response Time (63% response)
- <9KHz: 500mSec.
- >9KHz: 40mSec.
Output Ripple, P-P (% at max. input range frequency; 0% turn-down)
- Range 1: 0.5% (18KHz)
- Range 2: 0.5% (9KHz)
- Range 3: 0.7% (2100Hz)
- Range 4: 1.2% (525Hz)
Common Mode Rejection
60Hz: 97dB, DC: 120dB
- Common Mode Range
60Hz: 75Vrms, max.
DC: 1KV, max.
RFI Effect (1.5W, 470MHz at 1.5 ft.)
<1% of span error
Isolation
1000Vrms maximum input to output, input to case, output to case
Operating Temperature Range
- 4-20mA: -40 to 80°C (-40 to 176°F)
- 10-50mA: -40 to 60°C (-40 to 140°F)
Weight
0.58lbs
Agency Approval
CSA approved intrinsically safe for hazardous locations (File No. LR42272-70).
Ordering Information |
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