45
6.4.5 MTL5544D - Repeater Power Supply
Two channel, for 4/20mA HART® for 2- or 3-wire transmitters, two outputs
The MTL5544D provides a fully-floating dc supply for energising a conventional 2- or 3-wire
4/20mA transmitter located in a hazardous area, and repeats the current in other circuits
to drive two safe-area loads. For HART 2-wire transmitters, the unit allows bi-directional
transmission of digital communication signals superimposed on the 4/20mA loop current.
Separately powered current sources, such as 4-wire transmitters, can be connected but will
not support HART communication.
Hazardous area Safe area
Vs–
Vs+
20 to 35V dc
Ch 2
Ch 1
–
4/20mA
Load
+
–
4/20mA
Load
+
4/20mA
6
5
4
3
2
1
7
8
9
10
11
12
13
14
Com
Tx+
Input
I
I
I
Terminal Function
1 Current input
2 Transmitter supply +ve
3 Common
7 Ch2 output +ve via 220
Ω
for HART apps.
8 Ch2 output –ve
9 Ch2 output +ve
10 Ch1 output +ve via 220
Ω
for HART apps.
11 Ch1 output –ve
12 Ch1 output +ve
13 Supply –ve
14 Supply +ve
NOTE: For correct operation of the module, a suitable load must be present on both output channels.
This is of particular importance during testing, commissioning or maintenance activities when the
temporary disconnection, or absence, of a load can affect the transfer accuracy of the analogue variable.
Figure 6.24:
Top label
for MTL5544D
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