Flintec MCS-08 - Manual (Page 12)

MCS-08 Technical Manual, Rev. 1.04 December 2012 Page 12 of 52
4.2. Electrical Connections
Warning: Please always remember that MCS-08AD modules are very low voltage measuring instruments.
Your control cabinet design and proper installation increases the reliability and the performance of the
instrument. Please do not forget that the instrument must be powered off before inserting or removing any
peripheral connector. All required electrical connections should be done as described below.
4.2.1. Power Supply and Grounding
The power supply voltage of the instrument shall be between 12 V DC and 28 V DC. The current consumption
of the power supply will be calculated by multiplying 0.2 A and the quantity of instruments. The pin configuration
of the 24 V DC power supply connector located at the bottom front of the instrument is shown below in figure
4.3.
MCS-08AD
MCS-08IO
(front view)
MCS-08DP,
MCS-08PB,
MCS-08PN,
MCS-08MB and
MCS-08EN
(front view)
24V 0V 24V 0V
Warning: Do not forget to connect the Shield pin to the reference ground.
Figure 4.3 – The pin layout of 24 V DC connector
The quality of the instrument‟s ground will determine the accuracy and the safety of your measuring system. A
proper ground connection is needed to minimize extraneous electrical noise effects on the measurement. A
poor ground can result in an unsafe and unstable operation. It is important that the instrument should not share
power lines with noise-generating equipment such as heavy load switching, motor control equipments,
inductive loads, etc. If the condition of the power line in the plant is poor, prepare a special power line and
grounding. Before interfering the instrument, turn off the power and wait at least for 30 seconds.
4.2.2. Load Cell Connection
To avoid damages, the load cell wiring should be made carefully before energizing the instrument. Load cell
connection details are shown below in figure 4.4. In 4-wire installations the sense and excitation pins with the
same polarity should be short circuited at the connector side. If you have a junction box in your system, use a 6
wire cable between the MCS-08AD moduler and the junction box, and short circuit these pins at junction box for
better performance.
Load Cell
Connector 4 wire LC connection 6 wire LC connection
Warning: Connect the load cell cable shield to the reference ground or the
shield pin of the load cell connector.
Figure 4.4 – Load cell connection