Instructions

Table Of Contents

Supply options for MACX Analog (Ex)/MACX PL

105810_en_01 PHOENIX CONTACT 51

Figure 5-4 Supply by means of redundant power supplies

Example for supply via a MACX MCR-PTB… power terminal block

32 MACX MCR-SL-RTD-I temperature transducers (Order No. 2865065), 40 MACX MCR-

SL-NAM-R NAMUR signal conditioners (Order No. 2865997), and 26 MACX MCR-EX-SL-

RPSSI-I Ex i repeater power supplies (Order No. 2865340) are to be supplied at an operat-

ing voltage of 24 V DC.

First determine the current consumption of the modules from the package slips. For the tem-

perature transducers it is 40 mA per module and for the NAMUR signal conditioners it is

21 mA. The intrinsically safe repeater power supplies require 60 mA each.

Then determine the maximum total current consumption of all 98 modules.

The total current consumption of 3680 mA is less than the maximum permissible current for

supply via the MACX MCR-PTB…. To ensure that the built-in fuse in the MACX MCR-PTB

definitely trips in the event of a short circuit, the 24 V DC supply in this example is provided

by QUINT-PS/ 1AC/24DC/ 3.5 power supplies (Order No. 2866747), which provide a short-

circuit current of 15 A. The structure is shown in Figure 5-5 on page 52. The wiring is as

shown in Figure 5-4 on page 51.

1.2

2.2

3.2

3.3

1.1

2.1

3.1

Fault out

PWR 2

PWR 1

–

Faultsignal

GND

+24V

LFD

–

PSU

TBUS

–

PSU

Modul

I = n * I + n * I + n * I + ...

1 module12module23module3

I= 32 * 40 mA + 40 * 21 mA + 26 * 60 mA = 3680 mA < 3750 mA