4.3Wiring ST 3000 Transmitter
Summary |
| The transmitter is designed to operate in a | |
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| with loop resistance and power supply voltage within the operating | |
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| range shown in Figure 13. | |
| Figure 13 | Operating Range for ST 3000 Transmitters. | |
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| 1440 |
| 1200 |
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| = Operating |
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| Area |
Loop |
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| NOTE: A minimum of |
800 |
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| 250 0hms of loop | |
Resistance |
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| resistance is |
(ohms) |
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| necessary to support |
650 |
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| communications. Loop | |
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| resistance equals |
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| barrier resistance plus |
| 450 |
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| wire resistance plus |
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| receiver resistance. | |
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| 250 |
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| 0 | 10.8 | 16.28 | 20.63 25 | 28.3 | 37.0 | 42.4 |
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| Operating Voltage (Vdc) | 21012 | |||
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Loop wiring is connected to the transmitter by simply attaching the positive (+) and negative
(–)SIGNAL screw terminals on the terminal block in the transmitter’s electronics housing shown in Figure 14.
Each transmitter includes an internal ground terminal to connect the transmitter to earth ground. A ground terminal can be optionally added to the outside of the electronics housing. While it is not necessary to ground the transmitter for proper operation, we suggest that you do so to minimize the possible effects of “noise” on the output signal and provide additional protection against lightning and static discharge damage.
Note that grounding may be required to meet optional approval body certification. Refer to Section 1 CE Conformity (Europe) Notice for special conditions.
Optional lightning protection (option LP) can be ordered for transmitters that will be installed in areas highly susceptible to lightning strikes. Figure 14 shows the
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