Yokogawa Wireless Temperature Transmitter YTA510 - Manual (Page 7)

IM 01C50T03-01E 2-1
2. CONDITIONS OF COMMUNICATION LINE
2. CONDITIONS OF COMMUNICATION
LINE
2.1 Interconnection Between YTA
and BT200
WARNING
Do not attempt to use the BT200 in a dangerous
environment where explosive gas or inflammable
vapor is generated.
The BRAIN communication signal is superimposed
onto the 4 to 20 mA DC analog signal. Since the
modulated wave is a communication signal, superim-
posing it on the normal signal will, from basic prin-
ciples, cause no error in the DC component of the
analog signal. Thus, monitoring can be performed via
the BT200 while the transmitter is on-line.
As shown in Figure 2.1, there are two methods of
connecting the transmitter and the BT200: the first is to
use the BT200 connection hook provided in the
terminal box and the other is to use a terminal board or
relay terminals on the transmission line.
ϩ
Ϫ
YTA
BT200 BT200 BT200
F0201.EPS
BT200
Relay
terminals
4 to 20 mA DC
signal
transmission
line
Control room
Terminal
board
Distributor
Figure 2.1 Connecting the BT200
2.2 Communication Line Re-
quirements
Configure a loop that satisfies the following conditions
for mutual communication with the temperature
transmitter.
Power supply voltage : 16.4 to 42 V DC
Load resistance : R + 2Rc = 250 to 600
Ω
(See Figure 2.3 for the relationship between the
power supply voltage and load resistance.)
Load capacity
: 0.22
µ
F or less
Load impedance : 3.3 mH or less
Communication distance: 2 km (1.25 mile), when
CEV cable is used
Distance from the power line:
Output signal line : 15 cm (5.9 inch) or more
(do not use parallel wiring)
Input signal line : 100 cm (39.8 inch) or more
(do not use parallel wiring)
Input impedance of receiver connected to receiving
resistor: 10 k
Ω
more (at 2.4 kHz)
YTA
BT200
cc
F0202.EPS
Rc
Rc R
Power
supply
Figure 2.2 Communication line requirements
600
250
10.5 16.4 24.7 42
Power supply voltage E (V)
R=
0.0236
E–10.5
F0203.EPS
Load
resistance
R
(
Ω
)
Communication
applicable range
Figure 2.3 Relationship between power supply voltage
and load resistance