Deltabar PMD75B HART Electrical connection
Endress+Hauser 25
6.2.4 Cable specification
• Endress+Hauser recommends using twisted, shielded two-wire cables
• Cable outer diameter: 5 to 9 mm (0.2 to 0.35 in) depends on the used cable gland (see
technical information)
6.2.5 4-20 mA HART
A0028908
2 Block diagram of HART connection
1 Measuring device with HART communication
2 HART communication resistor
3 Power supply
The HART communication resistor of 250 Ω in the signal line is always necessary in
the case of a low-impedance power supply.
Take the voltage drop into consideration:
Maximum 6 V for a 250 Ω communication resistor
6.2.6 Overvoltage protection
Devices without optional overvoltage protection
Equipment from Endress+Hauser fulfills the requirements of the product standard IEC /
DIN EN 61326-1 (Table 2 Industrial Environment).
Depending on the type of port (AC supply, DC supply, input/output port) different test
levels according to IEC / DIN EN 61326-1 against transient overvoltages (Surge) are
applied (for devices with AC supply):
• Test level on AC power ports is 2000 V line to earth, 1000 V line to line (for devices with
4 to 20 mA, HART)
• Test level on DC power ports and input / output ports is 1000 V line to earth
Devices with overvoltage protection
• Spark-over voltage: min. 400 V DC
• Tested according to IEC / DIN EN 60079-14 sub chapter 12.3 (IEC / DIN EN 60060-1
chapter 7)
• Nominal discharge current: 10 kA
Overvoltage category
Overvoltage category II
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