MC5-IS User Guide

58

Startup and Basic Operation

Current Sink

MC5-IS has a possibility to sink current, i.e. MC5-IS acts as a device controlling the flow of current while a external device generates the supply voltage for the loop, both in the

E and the

ET

module. The maximum current it 25 mA.

Required settings Options/description

Quantity

Funct/Port

Current

ET: I(control)

or

E: I(control)

Using the ET module’s output terminals

When sinking current using the ET module’s output terminals, select

Funct/

Port

option

ET: I(control)

. The following picture displays the active terminals:

T / C I N T . R J

T / C , L o w V R , R T D

4 w m e a s

, ,

H A R T

T / C

W I R E S

O N L Y m e a s / s i m

S E N S O R M E A S U R E & S I M U L A T E

3 w m e a s

U o : 1 6 V

I o : 2 4 m A

P o : 1 4 5 m W

O U T P U T

E T

V , ,

M E A S U R E

m e a s / s i n k

C o m

L o w V

Note.

If you are simultaneously using the ET module’s output terminals and some of the ET module’s measuring terminals, there is no galvanic isolation between the measuring circuit and the current sinking circuit.

Using the E module’s output terminals

Select

Funct/Port

option

E: I(control) to sink current using the E modules terminals.

Active terminals:

T / C I N T . R J

4 w m e a s

Note.

V , ,

H A R T

T / C , L o w V R , R T D

T / C

W I R E S

O N L Y m e a s / s i m

S E N S O R M E A S U R E & S I M U L A T E

3 w m e a s

U o : 1 6 V

I o : 2 4 m A

P o : 1 4 5 m W

O U T P U T

E T

V , ,

M E A S U R E

L o w V

The output current of the E module is a “pure” analog signal without any embedded HART signal.

Generating/Simulating

Notes applying to both the

ET: I(control)

and the

E: I(control) ports:

Check the polarity of your connections. The arrows in the previous pictures describe the correct flow of current.

If the loop resistance of the external circuit is too high or infinite, the message “ O.LOAD” is displayed until the load is reasonable.

Warnings!

To avoid damages to MC5-IS' electronics, first select the correct Quantity and Function/Port. Then connect the circuit including the external supply to MC5-IS.

Make sure that you don’t exceed the maximum current allowed by the instrument under test.

If you open the mA generation loop, MC5-IS tries to maintain the current by decreasing the internal impedance. If you then close the loop again, the current is first too high, but returns quickly to the correct level. If this current peak could damage the components of the loop, make sure that the loop will not open or protect it against overcurrent. For the same reason, always enter 0 mA output before connecting the loop.

Next…

Current Measurement on page 39

Special Generations on page 67

Calibration, see Part D.

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