Introduction; Figure 1 Sf82 Online Monitor And Transmitter - Michell Instruments SF82 User Manual

SF82 Online User's Manual
1

INTRODUCTION

The SF82 Online Fast Response dew point hygrometer has been developed as a fast-
response, quick-to-install hygrometer system for the complete dew-point measurement
range of -60 up to +60°C (-76 up to +140°F) dew point, which covers many moisture
measurement applications.
The system comprises a programmable monitor configured to accept a 4–20 mA current
loop signal from the Michell thick-film dew-point transmitter. The span of the transmitter
is set to cover the measurement range -60 to +60ºC (-76 to +140ºF) dew point at
operating pressures up to 10 Mpa (100 barg / 1450 psig).
The monitor also has a re-transmission facility which buffers the transmitter output for
onward transmission to other systems. The transmitter input to the monitor is configured
as a 4–20 mA current loop signal and the re-transmitted output can be configured as
either a 4–20 mA or a 0–20 mA current loop signal (ranged as per the input).
Two alarm outputs are provided for connection to external systems. Alarm 1 provides
a set of single pole make contacts and Alarm 2 provides a set of changeover contacts.
Both sets are potential free and Alarm 1 contacts (single pole make) are rated at 250
V, 3 A and the Alarm 2 contacts (changeover) are rated at 250 V, 5 A.
A digital communications interface is also provided to enable retrieval of transmitter
values and fault status via Modbus RTU over RS485.
Figure 1 shows the monitor and the transmitter.
Michell Instruments
SF82 Online Monitor and Transmitter
Figure 1
INTRODUCTION
1