Output Wiring – Model 1700/2700 Intrinsically Safe Transmitters

WARNING

A transmitter that has been improperly wired or installed in a hazardous area could cause an explosion.

To reduce the risk of an explosion:

Make sure the transmitter is wired to meet or exceed local code requirements.

Install the transmitter in an environment that complies with the classification tag on the transmitter. See Appendix A.

Table 5-2Safety parameters

 

 

Value

 

 

 

Parameter

4–20 mA output

Frequency/discrete output

 

 

 

Voltage (Ui)

30 V

30 V

 

 

 

Current (Ii)

300 mA

100 mA

 

 

 

Power (Pi)

1.0 W

0.75 W

 

 

 

Capacitance (Ci)

0.0005 μF

0.0005 μF

 

 

 

Inductance (Li)

0.0 mH

0.0 mH

 

 

 

Hazardous area voltage

The Model 1700 or 2700 transmitter’s safety parameters require the selected barrier’s open-circuit voltage to be limited to less than 30 VDC (Vmax = 30 VDC). This voltage is the combination of the maximum safety barrier voltage (typically 28 VDC) plus an additional 2 VDC for HART communications when communicating in the hazardous area.

Hazardous area current

The Model 1700 or 2700 transmitter’s safety parameters require the selected barrier’s short-circuit currents to sum to less than 300 mA (Imax = 300 mA) for the milliamp outputs and 100 mA (Imax = 100 mA) for the frequency/discrete output.

Hazardous area capacitance

The capacitance (Ci) of the Model 1700 or 2700 transmitter is 0.0005 μF. This value added to the wire capacitance (Ccable) must be lower than the maximum allowable capacitance (Ca) specified by the I.S. barrier. Use the following equation to calculate the maximum length of the cable between the transmitter and the barrier:

Ci + Ccable Ca

Hazardous area inductance

The inductance (Li) of the Model 1700 or 2700 transmitter is 0.0 mH. This value plus the field wiring inductance (Lcable), must be lower than the maximum allowable inductance (La) specified by the I.S. barrier. The following equation can then be used to calculate the maximum cable length between the transmitter and the barrier:

Li + Lcable La

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Micro Motion® Model 1700 and 2700 Transmitters

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Emerson 1700, 2700 2Safety parameters, Hazardous area voltage, Hazardous area current, Hazardous area capacitance