Emerson Rosemount 935, Reference Manual

Page: 58 / 76

Power consumption
Table B-2: Detector and source maximum power consumption
Without heated optics
(maximum) With heated optics
(maximum)
Detector 150 mA 300 mA
Source 200 mA 300 mA
Electrical input protection
The input circuit is protected against voltage-reversed polarity, voltage transients, surges,
and spikes, according to EN50270.
Electrical outputs
• 0-20 mA current output: The 0-20 mA is an isolated sink option. You can also configure
this output as source.
The maximum permitted load resistance is 500 Ω.
• Communication network: The detector is equipped with an RS-485 communication
link that can be used in installations with computerized controllers.
Communication is compatible with the Modbus
®
protocol.
— This protocol is standard and widely used.
— It enables continuous communication between a single standard Modbus controller
(master device) and a serial network of up to 247 detectors.
— It enables connection between different types of Rosemount detectors or other
Modbus devices to the same network.
• HART
®
protocol: A digital communication protocol used to communicate between
intelligent field instruments and the host system.
Through the HART protocol, the detector can:
— Display setup.
— Reconfigure setup.
— Display and determine the detector status.
— Perform detector diagnostics.
— Troubleshoot.
B.2.1 Power consumption
Table B-3: Detector and Source Maximum Power Consumption
Without heated optic (max.) With heated optic (max.)
Detector 200 mA 250 mA
Source 200 mA 250 mA
Specifications Reference Manual
May 2022 00809-0100-4035
58 Emerson.com/Rosemount