Hitachi MICRO-EHV+ - Obv-485 A

Chapter 2 Specifications
2 – 38
2.20.2 OBV-485A
Name and function of each part
Type
OBV-485A
Weight
20g (0.04 lb.)
(3) Basic unit connector
(bottom)
(1) Communication port
(2) Communication LED
(5) Terminating resistance switch
(bottom)
(4) Analog input terminal
No.
Item
Description
(1)
Communication port
Communication port supports IEC programming function supporting Modbus-RTU master/slave
and general purpose communication.
*: IEC programming function is fixed to RS-485.
(2)
Communication LED
Flashes data transmission / reception.
(3)
Basic unit connector
This is a connector to basic unit.
(4)
Analog input terminal
Input terminal for analog voltage sigral
Cable diameter: Single wire: 0.2 mm
2
to 1.5 mm
2
Strand wire: 0.2 mm
2
to 1.0 mm
2
(5)
Terminating resistance
switch
This is a switch to select to enable / disable the 120Ω built-in termination resistor.
ON: Enabled
OFF: Disabled
Terminal layout
Pin No.
Signal
Meaning
Internal circuit
[8]
[1]
....
Socket connector
(Top view)
[1]
SG
Signal ground
Micro Processor
④ SDP
⑤ SDN
⑥ RDN
⑦ RDP
⑧ TERM
+
-
-
+
① SG
② VCC
③ N.C.
120
Terminating resistance switch
[2]
VCC
5V DC output
[3]
N.C
Not used
[4]
SDP
Send data +
[5]
SDN
Send data -
[6]
RDN
Receive data -
[7]
RDP
Receive data +
[8]
TERM
Not used
Analog input specifications
Item
Specification
Number of input
2 ch.
Input range
0 to 10V (10.24V max.)
Accuracy
1% (For the full-scale value)
Resolution
10-bit
Maximum external wiring length
Less than 3m
Input impedance
Approx. 100 k
Isolation
Between CPU and analog signal
Not isolated
Between channels
Not isolated