Observator Instruments OMC-183-ML User manual

OMC-183-ML Signal Conditioning Unit
Installation & technical user manual
Version 1.05 - 2019
Author: Observator Instruments

OMC-183-ML Manual Page 2
Revisions:
0.1 (26-08-2016) Conversion of OMC-183 hardware into OMC-183-ML hardware
Original OMC-183 manual version 3.17 was used to create this
installation & technical user manual
0.2(26-09-2016) Review version
1.01 (25-10-2016) First release
1.02 (24-9-2018) Correction in connection OMC-938 display (page 12).
1.03 (15-11-2018) Correction baud rate OMC-2900 output (fixed 4800 like both NMEA
inputs) .
1.04 (4-12-2018) Correction name ‘new OMC-406’to OIC-406
1.05 (8-10-2019) Correction connections OMC-9501 (page 11 chapter 2.9)

OMC-183-ML Manual Page 3
Index
1. INTRODUCTION .................................................................................................................... 5
1.1. INCLUDED TYPES OF OMC-183-ML....................................................................................5
2. INSTALLATION...................................................................................................................... 6
2.1. CONNECTIONS...................................................................................................................7
2.2. OMC-160 WIND SENSORS (NMEA)..................................................................................8
2.3. OMC-116 WIND SENSORS (NMEA)..................................................................................8
2.4. OMC-118 ULTRASONIC WIND SENSOR (RS422 NMEA).....................................................9
2.5. OMC-150/158 EEX WIND SENSOR....................................................................................9
2.6. OIC-406 TEMPERATURE &HUMIDITY SENSOR................................................................. 10
2.7. OMC-406 TEMPERATURE &HUMIDITY SENSOR.............................................................. 10
2.8. OMC-506 SINGLE BAROMETRIC PRESSURE SENSOR.(4-20MA) ....................................... 11
2.9. OMC-9501 BAROMETRIC PRESSURE SENSOR(S). (0 -2.5V /0-5V) ................................. 11
2.10. OMC-443 TEMPERATURE SENSOR (4-20MA) .................................................................. 12
2.11. OMC-938/939 DISPLAY (RS422 /OMC-2900)............................................................... 12
3. COMMISSIONING THE OMC-183-ML................................................................................. 13
3.1. CONNECTING YOUR PC /LAPTOP TO THE OMC-183-ML .................................................. 13
3.2. DEVICE STATUS.............................................................................................................. 13
3.3. USER SETTINGS QNH &QFE ......................................................................................... 14
4. MENU STRUCTURE ............................................................................................................ 15
5. EU DECLARATION OF CONFORMITY .............................................................................. 18

OMC-183-ML Manual Page 4
Page intentionally left blank

OMC-183-ML Manual Page 5
1. Introduction
The OMC-183-ML is a signal conditioning unit. It is designed to read and feed multiple sensors
and multiplex these signals to a serial signal. It does not log or store any data. Although the
OMC-183 can be used in many applications, this manual assumes it is used for meteorological
applications.
This manual is intended for qualified engineers with basic electronics knowledge. Usually the
OMC-183-ML is factory configured for your application and no changes besides some optional
user settings are required.
1.1. Included types of OMC-183-ML
In 2016 the hardware of the OMC-183 has been revised and all types of OMC-183 are included
into one hardware design. The following inputs* and outputs are available:
Inputs name
Functionality
0-5Vdc IN 1
Voltage in no.1
0-5Vdc IN 2
Voltage in no.2
0-5Vdc IN 3
Voltage in no.3
0-5Vdc IN 4
Voltage in no.4
0-24mA IN 1
Current in no.1
0-24mA IN 2
Current in no.1
0-24mA IN 3
Current in no.1
NMEA1 IN
Wind sensor 1
NMEA2 IN
Wind sensor 2
Outputs name
Functionality**
NMEA OUT
RS422 with NMEA
NMEA Return
RS422 with OMC-2900 format
RS232 TX
RS232 RX
Used for firmware upgrade,
configuration ***
* 4 analogue inputs of this list can be selected simultaneously as a maximum.
** The functionality of Current Loop (CL) output is no longer present in the new hardware design.
*** For backwards compatibility OMC-2900 is also at RS232 available after changing user
settings.

OMC-183-ML Manual Page 6
2. Installation
The OMC-183-ML is designed to be used indoors. Find a suitable location with the required
power and run your cables for all sensors.
Typically you will find the following sensors:
- wind sensor (OMC-160, OMC-116, OMC-118, OMC-150 or OMC-115)
- temperature & humidity sensor (OMC-406, OMC-443 or OMC-448)
- barometric pressure sensor (OMC-506: preferable build in OMC-183-ML housing*)
Output:
- Observator Display line: OMC-140, OMC-138/139 OMC-938/939
- OMC-data Online / OMC-DOL-HMS
Typical configuration with OMC-160 wind sensor, OMC-406 temperature & humidity sensor &
(dual) barometric pressure sensor.
* The OMC-506 must be vented outside via a tube whenever it is build in the OMC-183 housing and
the room is pressurized. We recommend to use a pressure head OMC-509 at the outdoor end of the
tube.
The OMC-183-ML is the replacement of the OMC-183 and got similar functionality. The additional
connectors are used in the MeteoLink products, some of these connectors may be functional in the
OMC-183-ML but others got a different functionality when compared to the MeteoLink concept.

OMC-183-ML Manual Page 7
2.1. Connections
The in the lid of the casing and on the printed circuit board a description of the functionality of
each pin is given. These descriptions are also used for MeteoLink products, therefore some
functionalities are available in the OMC-183-ML software.
Top row
Pin
Function
Bottom row
Pin
Function
1
GND [SUP] IN
17
GND
2
VIN [12-24VDC] IN
18
SUPPLY
3
NMEA_OUT_A
19
RS232_TX
4
NMEA_OUT_B
20
RS232_RX
5
SHIELD
21
RS485_422_IN_A
6
NMEA_RETURN_A
22
RS485_422_IN_B
7
NMEA_RETURN_B
23
GND
8
SHIELD
24
SUPPLY
9
GND [SUP]
25
0-5VDC_IN_1
10
SUPPLY
26
GND
11
NMEA1_IN_A
27
SUPPLY
12
NMEA1_IN_B
28
0-24mA_IN_1
13
GND [SUP]
29
GND
14
SUPPLY
30
CMOS_SUPPLY
15
NMEA2_IN_A
31
CMOS_TX
16
NMEA2_IN_B
32
CMOS_RX
Top row
Pin
Function
Bottom row
Pin
Function
40
GND
46
GND
41
RAIN_IN
47
SUPPLY
42
GND
48
0-5 V INPUT 2
43
SUPPLY
49
GND
44
RS485_A
50
SUPPLY
45
RS485_B
51
GND
Top row
Pin
Function
Bottom row
Pin
Function
60
0-24 mA INPUT 2
66
0-5 V INPUT 3
61
SUPPLY
67
GND
62
GND
68
SUPPLY
63
0-24 mA INPUT 3
69
0-5 V INPUT 4
64
SUPPLY
70
GND
65
GND
71
SUPPLY

OMC-183-ML Manual Page 8
2.2. OMC-160 Wind sensors (NMEA)
The Cup & Vane wind sensor got a standardized RS-422 output with NMEA protocol.
2 sensors can be connected.
OMC-183-ML
OMC-160
Sensor
1
2
GND [SUP]
9
13
1
Power GND
SUPPLY
10
14
2
Power 12-24V
NMEA1_IN_A
11
15
10
RS422 - out
NMEA1_IN_B
12
16
9
RS422 + out
Recommended cable: shielded 2x2x0,75mm2 twisted pair
OMC-160: NO Jumper on 13 -14
The optional heater will require a separate power supply.
Refer to OMC-160 manual.
2.3. OMC-116 Wind sensors (NMEA)
The Ultrasonic wind sensor got a standardized RS-422 output with NMEA protocol.
2 sensors can be connected.
OMC-183-ML
OMC-116
Sensor
1
2
GND [SUP]
9
13
1
Power GND
SUPPLY
10
14
2
Power 12-24V
NMEA1_IN_A
11
15
4
NMEA 0183 A
NMEA1_IN_B
12
16
3
NMEA 0183 B
Recommended cable: shielded 2x2x0,75mm2 twisted pair

OMC-183-ML Manual Page 9
2.4. OMC-118 Ultrasonic Wind sensor (RS422 NMEA)
Recommended cable: shielded 2x2x0,75mm2 twisted pair
Wires of OMC-118 come in pairs
Take care to use the correct (black) wires.
The junction box is part of the optional
bracket OMC-122(-M).
2.5. OMC-150/158 EEx Wind sensor.
The old OMC-158 is not compatible met the OMC-183-ML, however the new OMC-158-2
contains RS-422 NMEA output signal and is compatible. The wiring is similar to the
OMC-160.
OMC-183-ML
OMC-118
GND [SUP]
13
3
Black
POWER SUPPLY V- (GND)
SUPPLY
14
4
Red
POWER SUPPLY V+ (12-24V)
NMEA1_IN_A
15
5
Black
RS 422 TXA (-)
NMEA1_IN_B
16
6
Green
RS 422 TXB (+)

OMC-183-ML Manual Page 10
2.6. OIC-406 Temperature & Humidity sensor.
The OIC-406 has NMEA output. Connecting the basic node to OMC-183-ML is possible
by using NMEA1 IN or NMEA2 IN.
2.7. OMC-406 Temperature & Humidity sensor.
The old OMC-406 is a less accurate sensor, and got two 4-20mA analog outputs. These
signals can be connected to OMC-183-ML by using two of the analog current input ports
for example current inputs 2 & 3:
Recommended cable: shielded 2x2x0,75mm2 twisted pair
OMC-183-ML
OIC-406 (NMEA)
GND [SUP]
13
1
GND [SUP]
SUPPLY
14
2
SUPPLY
NMEA2_IN_A
15
3
NMEA_OUT_A
NMEA2_IN_B
16
4
NMEA_OUT_B
OMC-183-ML
OMC-406 (4-20mA)
GND
62
Yellow
Power GND
SUPPLY
61
Green
Power +24V
0-24 mA INPUT 2
60
Brown
4-20mA out
(temperature)
0-24 mA INPUT 3
63
White
4-20mA out
(humidity)