Power Supply - ABB ttr200 Operating Instruction

7.3

Power supply

Two-wire technology, polarity safe; power supply lines = signal
lines
NOTICE
Following calculations apply for standard applications. This
should be taken into consideration when working with a
higher maximum current.
Input terminal voltage
— Non-Ex application:
U = 11 ... 42 V DC
S
— Ex applications:
U = 11 ... 30 V DC
S
Max. permissible residual ripple for input terminal voltage
— During communication in accordance with HART FSK
"Physical Layer" specification.
Undervoltage detection on the transmitter
— If the terminal voltage on the transmitter falls below a
value of 10 V, this may lead to an output current of I
3.6 mA.
Maximum load
— R = (supply voltage – 11 V) / 0.022 A
B
Fig. 10: Maximum load depending on input terminal voltage
A TTR200 B TTR200 in Ex ia design C HART communication
resistance
Maximum power consumption
— P = U x 0.022 A
s
= 24 V  P
— e. g. U
s max
14 OI/TTR200-EN Rev. B | TTR200
= 0.528 W
Voltage drop on the signal line
When connecting the devices, note the voltage drop on the
signal line. The minimum supply voltage on the transmitter
must not be undershot.
A
Fig. 11
A Transmitter B Supply isolator / PCS input with supply / Segment
coupler
U : Minimum supply voltage on the transmitter
1min
U : Minimum supply voltage of the supply isolator /
2min
DCS input
R: Line resistance between transmitter and supply
isolator
R : Resistance (250 Ω) for HART functionality
250
≤
a
Standard application with 4 ... 20 mA functionality
When connecting these components, observe the following
condition:
U ≤ U - 22 mA x R
1min 2min
Standard application with HART functionality
Adding resistance R
U :
2min
U ≤ U - 22 mA x (R + R
1min 2min
For HART functionality, use supply isolators or DCS input
cards with a HART marking. If this is not possible, a resistance
of ≥ 250 Ω (< 1100 Ω) must be added to the interconnection.
The signal line can be operated with or without grounding.
When establishing a ground connection (minus side), make
sure that only one side of the terminal is connected to the
potential equalization.
R
+ +
250
U U
1 2
- -
R
increases the minimum supply voltage:
250
)
250
B
A11122