Input/Output Signal; Sampling System - Michell Instruments Liquidew I.S. User Manual

Liquidew I.S. User Manual
1.4.1

Input/Output Signal

The terminal blocks for the signal input, signal output and alarm output are located on
the back panel of the control unit (see Figure 8) .
• Signal Input
There are two 4...20 mA signal input channels from the dew-point and
temperature sensors to the control unit. Both input channels are isolated by
built-in galvanic type I.S. barriers.
• Signal Output
There are three 4...20 mA linear signal output channels.
There is one RS485 Modbus RTU digital communication port. Please refer to
Appendix B.
• Alarm Output
There are four alarm relays. Alarms 1 and 2 are Form C contacts rated 30 V
DC 5A, non-inductive load. Alarms 3 and 4 are Form A contacts rated 30 V
DC 5A, non-inductive load. The control actions and set points of these four
alarms are user-programmable. A fault alarm with adjustable set points is
also included.
1.5

Sampling System

The Liquidew I.S. requires a clean sample of the process liquid that meets the
temperature, pressure and flow requirements of the transmitter. The design of the
sampling system will depend on the specific application.
The requirements for the sample liquid going into the sensor block are as follows:
• Temperature: 0...+40 °C (+32...+104 °F) (maximum +60 °C (+140 °F))
NOTE: Sample temperature must be above the moisture saturation
temperature of the sample fluid
• Maximum pressure: 5 MPa (50 barg / 725 psig)
• Flow rate: 0.1...0.3 l/min (0.026...0.079 GPM)
NOTE: Contact Michell Instruments if you wish to order a specific sampling
system.
Please refer to the ES70L Premium Sampling System Instructions if a Michell sampling
system has been ordered with the Liquidew I.S.
Michell Instruments
INTRODUCTION
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