YDOC ML-2012/13 User manual

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 1
Type ML-2012/13
Low power GPRS data logger
Title : User Manual ML-2012/13 Date : 30-Oct-2014
Version : 1.4

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 2
WARNING
THE FOLLOWING OPERATING INSTRUCTIONS ARE FOR USE BY QUALIFIED
PERSONNEL ONLY. TO AVOID DAMAGE OR MALFUNCTION, DO NOT PERFORM
ANY OPERATING OTHER THAN THAT CONTAINED IN THIS MANUAL. ANY
OPERATOR SHOULD BE SKILLED WITH A TECHNCAL BACKGROUND BEFORE
OPERATING THE DEVICE.
PREFACE
Congratulations!
With your purchase of the ML-2012/13 Low Power data logger with GPRS Capabilities.
This manual describes the operation and (hardware) installation of the ML-2012/13 Data logger.
The chapter Getting Started briefly describes the ML-2012/13 data logger, prepares you to install it, and
tells you how to put it into operation.
The Chapter Operating Basics covers basic principles of operation of the data logger. The operating
interface (menu) and the tutorial examples, rapidly help you to understand how your data logger operates.
The Chapter Reference teaches you how to perform specific tasks and provides a complete list of
operating tasks and useful background information.
The Appendices provide a list with all available options, and other useful information.
We recommend you to read this manual carefully before installation of the ML-2012/13.
Warranty
All YDOC instruments are warranted against defective materials and workmanship. Any questions with
respect to the warranty mentioned above should be taken up with your YDOC Distributor.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 3
Table of Contents
1 Product Description ............................................................................................................................... 5
1.1 Editions ......................................................................................................................................... 6
1.1.1 ML-2012.................................................................................................................................... 6
1.1.2 ML-2013.................................................................................................................................... 7
2 Getting started ....................................................................................................................................... 8
2.1 Vibration........................................................................................................................................ 8
2.1.1 Do’s and Don’ts ........................................................................................................................ 8
2.2 Inserting the SIM-card .................................................................................................................. 8
2.3 Power on for the First time............................................................................................................ 9
2.4 Connect to a PC ........................................................................................................................... 9
3 Operating Basics ................................................................................................................................. 10
3.1 Configuration menu .................................................................................................................... 10
4 Reference ............................................................................................................................................ 16
4.1 Principle of Operation ................................................................................................................. 16
4.1.1 Sample interval ....................................................................................................................... 16
4.1.2 Data logging interval ............................................................................................................... 16
4.1.3 Send Interval........................................................................................................................... 16
4.1.4 Example .................................................................................................................................. 16
4.2 SDI-12......................................................................................................................................... 17
4.2.1 SDI-12 Hardware .................................................................................................................... 17
4.2.2 SDI-12 Wiring ......................................................................................................................... 17
4.2.3 SDI-12 Baud Rate and Frame Format.................................................................................... 18
4.3 RS232 ......................................................................................................................................... 18
4.4 RS485 ......................................................................................................................................... 19
4.5 Analog Inputs (4..20mA) ............................................................................................................. 20
4.5.1 Loop Powered Devices........................................................................................................... 20
4.6 Analog Differential Inputs (ML-2013 only) .................................................................................. 20
4.6.1 Differential input ports theory of operation.............................................................................. 20
4.6.2 Common mode noise rejection............................................................................................... 20
4.6.3 Using Load Cells With the ML-2013 ....................................................................................... 20
4.6.4 Bridge of Wheatstone ............................................................................................................. 21
4.6.5 Excitation Output. ................................................................................................................... 21
4.6.6 Analog Differential input 5....................................................................................................... 22
4.6.7 Analog Differential input 6....................................................................................................... 22
4.6.8 Calibration of Differential inputs.............................................................................................. 22
4.6.9 Overall Calibration .................................................................................................................. 22
4.7 Digital inputs ............................................................................................................................... 23
4.7.1 Pull up type ............................................................................................................................. 23
4.7.2 Pull down type ........................................................................................................................ 23
4.8 Coil input ..................................................................................................................................... 23
4.9 Alarming...................................................................................................................................... 24
4.9.1 Alarming - principal of operation............................................................................................. 24
4.10 Firmware Upgrade ...................................................................................................................... 25
4.10.1 When to use Firmware upgrades........................................................................................ 25
4.10.2 Firmware upgrade procedure ............................................................................................. 25
4.10.3 Firmware upgrade over the air ........................................................................................... 26
4.10.4 Firmware Driver limitations ................................................................................................. 26
4.10.5 Power Switch Limitations.................................................................................................... 26
4.10.6 Modem ................................................................................................................................ 26
4.10.7 Modem Firmware Upgrade ................................................................................................. 26
4.11 SD-card....................................................................................................................................... 27
4.11.1 Inserting an SD-card........................................................................................................... 27
4.12 Data Format................................................................................................................................ 27
Header: ............................................................................................................................................ 27
Parameter Code: ............................................................................................................................. 28

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 4
Parameter Name: ............................................................................................................................ 28
Parameter Unit:................................................................................................................................ 28
4.12.1 D-Records........................................................................................................................... 28
Parameter Code: ............................................................................................................................. 28
Parameter value: ............................................................................................................................. 28
4.12.2 System-records................................................................................................................... 29
System Message: ............................................................................................................................ 29
Additional System Message: ........................................................................................................... 29
4.12.3 Data Modifiers..................................................................................................................... 29
4.13 Transmission of the data log file................................................................................................. 30
4.14 Input-drivers ................................................................................................................................ 30
4.14.1 Analog sensors ................................................................................................................... 30
4.14.2 Digital Pulse Sensor ........................................................................................................... 31
Example configuration Rain Measurement...................................................................................... 31
Counter ............................................................................................................................................ 32
Quantity............................................................................................................................................ 32
Rate ................................................................................................................................................. 32
4.15 Power supply .............................................................................................................................. 33
4.15.1 Internal RTC backup battery............................................................................................... 33
4.15.2 Power consumption & Battery Life ..................................................................................... 33
5 Pin configuration.................................................................................................................................. 34
5.1 ML-2012...................................................................................................................................... 34
5.2 ML-2013...................................................................................................................................... 35
5.3 Pin Description............................................................................................................................ 36
5.3.1 Analog Inputs .......................................................................................................................... 36
Analog Input 1 to 4........................................................................................................................... 36
Analog Input 5 to 8 (ML-2013 only) ................................................................................................. 36
5.3.2 RS 485 A & B.......................................................................................................................... 36
5.3.3 Power Switch .......................................................................................................................... 36
5.3.4 VBAT + ................................................................................................................................... 36
5.3.5 RX & TX COM 1 & Com 3 ...................................................................................................... 36
5.3.6 SDI-12 Hi ................................................................................................................................ 36
5.3.7 Digital inputs ........................................................................................................................... 36
5.3.8 +3V6 ....................................................................................................................................... 36
5.3.9 Antenna placement and field strength .................................................................................... 37
6 Maintenance and Repair ..................................................................................................................... 37
6.1 RTC Lithium Battery replacement .............................................................................................. 37
6.2 Recalibration ............................................................................................................................... 38
6.3 XRAY .......................................................................................................................................... 38
7 Safety .................................................................................................................................................. 38
7.1 Power supply .............................................................................................................................. 38
7.2 ESD............................................................................................................................................. 38
8 Environment and disposal ................................................................................................................... 39
9 Transport and Storage ........................................................................................................................ 39
10 Specifications................................................................................................................................... 40
11 EU Declaration of Conformity .......................................................................................................... 41
11.1 ML-2012...................................................................................................................................... 41
11.2 ML-2013...................................................................................................................................... 42
12 Supported serial transponders......................................................................................................... 43
13 Trouble shooting .............................................................................................................................. 44
Customer Response Form ......................................................................................................................... 45

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 5
1Product Description
The ML-2012/13 is designed to retrieve, and store data from various sensors. This data is logged onto the
embedded SD-card. Also the stored data can be send from the data logger to any remote computer you
like. To use this feature, you need a valid SIM-card. Contact your local telecommunications supplier for
more information on the SIM card you will need. The unit accepts various power sources, selectable by
the different version types. The user should connect his sensor(s) of preference to the connector board of
the device. Captured data can be stored, send, visualized and manipulated in many ways.
The ML-2012/13 data logger is a small, ultra low power, high-end data logger with built-in QUAD-band
GPRS-modem. This small data logger, is further provided with an internal temperature sensor, 2 GB
micro SD-card and an SIM card slot. The logger can be powered by an internal 3.6 Volt Lithium battery
that will last for years when the logger is configured in a low-power mode.
The ML-2012 data logger can acquire physical signals by 4 current loop inputs, 4 digital inputs The ML-
2013 data logger can acquire physical signals by 4 current loop inputs, 4 digital inputs and 2 hires
amplified differential voltage inputs, which can be used to connect pyranometers or in combination with a
stable excitation voltage to connect “Wheatstone resistive bridge sensors” like load cells.
The data logger is provided with generic serial port drivers to capture measurements from ASCII,
MODBUS/RTU, NMEA or SDI-12 transponders, custom drivers can be developed on request. External
sensors/transponders can be powered by the data logger itself, to prevent them to consume power while
the data logger is a sleep. The excitation voltage is switched off during sleep as well.
Its key features are;
- A maximum sample rate of 4 Hz,
- Recording length up to 2 GB,
- Four channel 12 bits A/D Convertor for accurate current loop measurements,
- Two channels 16 bits differential A/D convertor for low voltage measurements (ML-2013 only),
- Internal micro SD-card with standard FAT-32 File system for easy use with a PC,
- Various analogue and digital inputs for use with sensors (see specification sheet),
- Easy configuration by menu’s of embedded menu,
- Can be used with Windows XP, Vista and W7
- Low power / long Battery life (see specification sheet),
- Embedded GPRS/GSM modem for remote operation,
- Quad band modem for use all over the world,
- Alarming by SMS and data delivery by e-Mail, FTP or TCP
- Internal voltage convertor for supplying 12 VDC power to the connected sensor(s),
- Stable excitation voltage to power Wheatstone bridged sensors (ML-2013 only),
- Firmware upgrade over the air for adding new features to your device.
- Remote configuration over the air, for adjusting your configuration from remote.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 6
1.1 Editions
The following editions are available:
Code
Description
Remarks
ML
-
2012
Lithium powered data logger in IP65 ABS
enclosure with external GSM antenna.
Lithium battery not included.
ML
-
2013
Lithium powered data logger in IP67 PA66/GF20
enclosure with integrated GSM antenna.
Lithium battery not included.
ML
-
2013
-
PV
As ML-2013, but with NiMH AA solar charger
integrated in cover.
NiMH AA batteries not included.
ML
-
2013
-
DC
As ML-2013, but with 8 .. 30V DC-adapter
integrated in cover.
To connect the logger to an
external VDC source.
ML
-
2013
-
AC
As ML-2013, but with 85 .. 265V AC-adapter
integrated in cover.
To connect the logger to an AC
power grid.
ML
-
2012/13
-
PCB
As ML-2012/13, but without enclosure and
antenna.
PCB only
The data logger will be supplied without pre-mounted cable glands, giving the user the freedom to choose
the number and size of the glands them self. Although glass fiber reinforced polyamide is a tough
material, drilling gland holes is easy. We recommend removing the PCB before drilling.
1.1.1 ML-2012
The IP65 ABS enclosure of the ML-2012 has a small form factor very suitable to be integrated inside an
existing cabinet or the bucket of a rain gauge.
1) SDI-12 and power switch
2) Analog inputs
3) Digital inputs
4) RS232 connector
5) RS485 connector

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 7
1.1.2 ML-2013
The waterproof IP67 enclosure of the ML-2013 exists out of a casing and cover of glass fiber reinforced
polyamide (PA66/GF20) with in between a silicon gasket. The ML-2013 can be used outdoors.
1) Analog inputs
2) RS232 connector
3) Excitation DC/DC convertor
4) Digital inputs
5) SDI-12, power switch and
Excitation connector
6) RS485 connector
7) Power switch DC/DC convertor
8) RTC clock battery
9) Power supply connector
10) Fuse
11) Processor
12) Antenna Connector
13) Quad Band Modem
14) USB Connector
15) SIM & SD-card Holder

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 8
2Getting started
2.1 Vibration
At all times the ML-2012/13 must be protected against vibrations. These vibrations can harm the
performance of the data logger. Especially the real time clock can be harmed by long-lasting vibrations
2.1.1 Do’s and Don’ts
Do’s
- Always provide a dry and clean environment when you open the case of the ML-2012/13,
- When you open the case, use a Philips screwdriver of 2mm for loosening the screws,
- Protect the data logger against mechanical stress and vibrations
Don’ts
- Don’t try to use a plain screwdriver for loosening the screws, you will damage the screws,
- Avoid touching the PCB directly.
2.2 Inserting the SIM-card
The wireless data functions will only work when an activated SIM, with a valid subscription is placed in the
ML-2012/13. In the menu the configuration and network settings must also mach to those supplied by the
SIM card provider. The pin code of the SIM card must be removed prior to insertion in the data logger. To
prevent problems with the SIM card it can be inserted in a mobile phone or GSM data modem. In a
Mobile phone or GSM modem the GPRS, SMS and GSM data functionality can be tested.
When you have obtained a SIM-card, you can insert it into the SIM-card-holder.
Beware:
•Remove the PIN code (this can be done with the use of a mobile
phone),
•Check the settings of your mobile provider,
•Check the settings for communicating via FTP / Email / Native TCP,
•Check the capability of data communication for your service-provider,
•Make sure the SIM-card is installed correctly, and not upside down.
The Oblique side of the card should be visible. (see picture).
•Installation of the SIM card needs to be done in a clean and dry
environment.
•Avoid contact with the electronic parts around the SIM card.
•Remove power before changing or inserting a SIM card.
•The same applies to the SD-card.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 9
ESD Attention: Although the ML-2012/13 is designed to withstand certain amounts of electrostatic
discharge, it is advised to avoid discharged risks. Especially when the housing is open and the electronic
parts are exposed. Please do not touch the PCB if you don’t have to. It is strongly recommended to use
an earthed wrist-band when touching the PCB.
The data logger must be handled with care and never exposed to ESD discharges. When installing a
sensor or other wiring, make sure there is no power on both devices. ESD discharges could cause
invisible damage. This endangers long term stability and proper operation.
2.3 Power on for the First time
In the factory the data logger is programmed with the necessary system information. This information is
viewable in the menu. The data logger is ready to use out of the box if the preparations are checked.
•SIM card is inserted,
•SD-card is inserted,
•Internal battery, or mains power is connected
•Antenna is connected.
Next, connect your sensors, please consult your sensor’s manual for wiring.
2.4 Connect to a PC
OS compatibility: The ML-2012/13 can be connected to any PC with USB 2.0 running on Microsoft
Windows XP, Windows Vista or Windows 7
Installation procedure for the internal USB adapter for Windows XP is given on the CD.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 10
3Operating Basics
3.1 Configuration menu
The ML-2012/13 can be configured by means of terminal emulation software like ‘hyper terminal’. Our
own terminal emulation software ‘YDOC-terminal’ can be downloaded from www.your-data-our-
care.com
The menu is comprehensive and easy to use. For each different sensor the same approach is used.
Below, one example is given to fully understand the operation of the menu. The example takes you
through a configuration from start to final stage. Only a few menu-items are used in this example, for a
complete overview of all menu-items, see chapter Reference. All menu items use the same approach
which is explained in this example. This example explains only the configuration of the firmware, NOT the
wiring. For wiring information see the reference.
Example:
Let’s Configure a ML-2012/13 for operation with the following:
- Analog pressure transmitter 4 .. 20mA
- CT2X conductivity / temperature sensor (INW)
- FTP data output
- EMAIL data output
Connect the logger to a free USB port on your computer and open with a terminal emulator the virtual
COM-port (e.g. COM7) as assigned by Windows to the logger. The first time Windows will ask (if not
already installed) for an USB-driver, which can be downloaded from our website as well.
When the terminal emulator has opened the COM-port, press:
<Ctrl>A<Shift>M<Ctrl>D to enter the configuration menu.
You’ll see a screen similar to this:
Running
Configuration Menu ML-2013 Logger Version 1.6 Build 1
First we like to give this data logger appropriate identification codes.
So, press 3 <Configuration Setup>
[0] Run
[1] Date & Time >> 2013/07/05 12:58:21
[2] System Information >> 300238
[3] Configuration Setup >> Brasil
[4] Configuration Review
[5] Maintenance
>

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 11
You’ll see this screen:
First Rename your Device by
Selecting option 1
(General Settings)
After selecting “General Settings” the screen will look like this:
< General settings>
1. Press 1 and enter the name of your preference
2. Choose your data logging interval. We used 10 minutes, and NO Alarming.
3. Enter the deployment date & time. This can be a time in the future when logger should start working.
We will use the actual date & time to start right away.
4. Exit and save changes.
5. Now, the overall configuration is setup and we proceed with the configuration of the sensors and data
output.
Next type 7 for Analog sensors
Choose 1 for Port 1 (mA) and the next screen will appear:
General settings
[0] Exit
[1] System Name >> YDOC
[2] Data logging interval >> Normal 00:01:00; Alarm Not Used
[3] Direct Data output on Data Alarm >> Off
[4] Deployment date and time >> 2013/07/05 20:17:42
[5] Time zone >> 2
[T] SD-card test >> Passed
>
Configuration Setup
[0] Exit
[1] General settings >> YDOC
[2] Modem settings
[3] NTP Time update >> Not Used
[4] Alarm SMS >> Not Used
[5] SMS Commands >> Not Used
[6] Internal sensors >> Not Used
[7] Analog sensors >> Not Used
[8] Digital sensor >> Not Used
[ ] GSM signal sensor >> Not Used
[A] Serial port 1 >> Not Used
[B] Serial port 2 >> Not Used
[C] FTP output >> Not Used
[D] TCP output >> Not Used
[E] Email output >> Not Used
>
Analog sensors
[0] Exit
[1] Port 1 (mA) >> Not Used
[2] Port 2 (mA) >> Not Used
[3] Port 3 (mA) >> Not Used
[4] Port 4 (mA) >> Not Used
[5] Port 5 (mV) >> Not Used
[6] Port 4 (mV) >> Not Used
[T] Analog input test >> Passed
>

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 12
1. Assign a name to the sensor (option 1: Name)
2. Set the power switch to enabled and enter the warm-up time. (the power switch will supply the sensor
with 12 Volts, and will be activated the time you specify, before a measurement is taken)
3. Set the sample interval. We use 10 seconds, to quickly check the sensor’s operation. A high range
sample interval is no problem for the battery-life, because the sensor will sleep until its data logging
interval is reached. So don’t be modest with the sample interval. It gives you great comfort.
4. Set the parameter name.
5. Set both minimum (option 6) and maximum (option 7) values of your sensor at 4mA and at 20mA. If
you don’t know those values you could determine the scaling by measuring two calibration points
(option 8). Those calibration points don’t have to be at the sensors absolute minimum and maximum,
but just two different points within the range of the sensor. (e.g. a measurement at 1m water level and
a measurement at 2m water level, while the sensors range is 0..10m)
6. If necessary option 9 can be used to perform an offset correction by measuring a single calibration
point.
7. Save and Exit
Your screen will look similar to the one underneath:
Analog sensor
Analog sensorAnalog sensor
Analog sensor
[0] Exit
[0] Exit[0] Exit
[0] Exit
[1] Name >> Analog
[1] Name >> Analog[1] Name >> Analog
[1] Name >> Analog
[2] Sensor power switch >> Disabled
[2] Sensor power switch >> Disabled[2] Sensor power switch >> Disabled
[2] Sensor power switch >> Disabled
[3] Sample interval >> Normal 00:00:01; Alarm Not Used
[4] Port mode >> 4-20 mA
[5] Parameter >> Analog 1
[6] Parameter value at 4mA >> 0 units
[7] Parameter value at 20mA >> 100 units
[8] Determine linear conversion function (2 calibration points)
[ ] Determine linear offset only (1 calibration point)
[R] Remove
>
Analog sensor
[0] Exit
[1] Name >> Upperstream
[2] Sensor power switch >> Enabled; Warm up time 00:00:01
[3] Sample interval >> Normal 00:00:10; Alarm Not Used
[4] Port mode >> 4-20 mA
[5] Parameter >> Water level
[6] Parameter value at 4mA >> 0 m
[7] Parameter value at 20mA >> 10 m
[8] Determine linear conversion function (2 calibration points)
[ ] Determine linear offset only (1 calibration point)
[R] Remove
>

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 13
Now we add the CT2X to the system:
Go to menu-option A <serial port 1> => RS 485 sensors
Choose the INW CT2X (option 2)
Your screen should look like this:
Multiple CT2X sensors can be connected to an RS485 bus so you need to specify its address (assuming
1 in this example). This sensor is a multiple parameter sensor, so please specify which you want to log.
Attention:
Because this is a digital sensor, it takes a little bit more time to measure than an analog sensor. So don’t
set the sample interval of digital sensors too short. 1 second is possible, but probably not ¼ sec. Just to
be sure we choose 10 sec. Consult the manual of your digital sensor and check the response time. The
sample-interval must be larger than the response time of the sensor.
Now your sensors are added to the configuration of the ML-2012/13.
RS485 Sensors
[0] Exit
[1] Generic MODBUS/RTU
[2] INW CT2X
[3] INW DO
[4] INW PT2X type A
[5] INW PT2X type B
[6] INW PT12
[7] INW TempHion
[8] OMC506
>
INW CT2X sensor
[0] Exit
[1] Name >> INW CT2X
[2] Port settings >> Port 1; 38400 Baud; RS485; Address 1
[3] Sensor power switch >> Disabled
[4] Sample interval >> Normal 00:00:10; Alarm Not Used
[5] Temperature >> Temperature
[6] Pressure >> Pressure
[7] Conductivity >> Not Used
[8] Conductivity nLF >> Not Used
[ ] Salinity >> Not Used
[R] Remove
>

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 14
Next thing is the setup of the data outputs.
Before that, we have to configure the general modem settings for GPRS operation. Consult your GPRS-
provider for the correct local settings. In the reference, a table is included with some international GPRS-
providers and their settings. These settings might have been changed.
Go to Menu-option 2 <Modem settings>
Now we can setup the FTP, TCP and Email output
Therefore go to menu-option:
-C Ftp Output.
-D Tcp output
-E Email output
Enter your server-settings.
It should look like this:
Email settings
Beware:
Some providers
strictly check the
Originator
address. So
make sure this
address is valid.
Now perform an Email test and check if it is working right.
It is strongly recommended to include some internal sensors in the configuration, because of the
monitoring of the performance of the data logger itself. Most users like to keep track of the battery-life for
example.
[0] Exit
[1] Name >> Email
[2] Send interval >> Normal 01:00:00; Alarm Not Used
[3] Send delay >> Not Used
[4] SMTP Server >> smtp.provider.com
[5] SMTP Port >> 25
[6] User name >> reh6a01
[7] Password >> ********
[8] Originator address >> [e-mail]
[ ] Destination address >> [e-mail]
[A] Subject >> YDOC upperstream
[R] Remove
[T] EMAIL test >> Not Done
>
Modem settings
[0] Exit
[1] Modem during sleep >> Off
[2] Frequency selection
[3] Provider selection
[4] APN Acces point >> internet
[5] APN User name >> kpn
[6] APN Password >> kpn
[7] Dial-in Autorisation >> Off
[S] GSM Signal strength >> Passed
[T] APN Login test >> Not Done
>

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 15
Go To menu-option 6 <internal sensors>
A sample interval of 1 second is fine. All internal sensors are very fast.
Set the “Battery Replaced” to “Yes”, only when you installed a new battery.
Select the items you like to be informed about.
See the reference for a complete description of the items.
Now your data logger is configured and ready to use.
To check your wiring and sensors, you can evaluate the actual values.
To see them press: <Ctrl>A<Shift>V<Ctrl>D
The result should be like this:
Internal sensors
[0] Exit
[1] Name >> Internal
[2] Sample interval >> Normal 00:00:01; Alarm Not Used
[3] Battery Capacity (mAh) >> 17000
[4] Battery replaced >> Yes
[5] Rest Capacity >> Rest Capacity
[6] Rest Power >> Not Used
[7] Processor Temperature >> Processor Temperature
[8] Voltage >> Voltage
[ ] Current >> Not Used
[A] Max Current >> Not Used
[B] Min Current >> Not Used
[C] Average Current >> Not Used
[D] Free Disk Space >> Not Used
[E] Operating Cycle >> Not Used
[F] Free Disk Space >> Not Used
[R] Remove
>
13/07/05 14:22:04 Actual Values ML-2012/13 Logger Version 1.6 Build 1
AIN1 Waterlevel -25 meters MSL
TMP Temperature 20.2 C
PRS Pressure 0.2 psi
RCi Rest Capacity 100 %
PTi Processor Temperature 57.4 C
Vi Voltage 3.6 V
Ci Current 82 mA

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 16
4Reference
4.1 Principle of Operation
Your ML-2012/13 Data logger is capable of collecting and storing data of multiple sensors. To accomplish
this, many tasks are performed. These “tasks” are scheduled and executed on their specified time. The
timing of this process is very important and is determined by the internal scheduler. This scheduler keeps
track of all the internal states of the various tasks and assigns processor time to the different tasks. Each
task is executed on its own interval. To understand more about this, Fist we explain the different intervals.
There are three different intervals:
1) Sample Interval
2) Data Log Interval
3) Send Interval
4.1.1 Sample interval
The sample interval is the interval on which a sample from the sensor is taken (expected). So,
measurements from sensors are done at the sample interval. The sample interval is valid ONLY when the
device is in the active state. When the data logger is in sleep-mode, the tasks, triggered by the sample
interval will NOT execute.
4.1.2 Data logging interval
This interval determines when a data value, obtained by the sample interval-task, is stored onto the SD-
card. This type of interval is ALWAYS valid. So, even when the data logger is in sleep-mode, it will wake
up when the Data logging Interval has reached its count.
4.1.3 Send Interval
The send interval determines the interval on which data is send, via the internal modem. This interval is
ALWAYS valid, even if the data logger is in sleep-mode.
4.1.4 Example
Let’s evaluate the following settings of the data logger:
- Sample Interval: 5 seconds
- Data Log Interval: 10 minutes
- Send Interval: 3 hours
When the configuration is ready and the user disconnects the USB-Cable;
1. Data logger is switched into sleep-mode, and current draw is reduced to a minimum level.
2. The Sample interval of 5 seconds is discarded, because this interval is only active when the data
logger is NOT in sleep-mode. So nothing happens until the Data Log interval has reached his count.
(So this happens on 0, 10, 20, 30, 40, 50 minutes every hour)

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 17
3. When the Data Log Interval count has reached his count, the data logger will awake from the sleep
mode, and will take a sample and stores the data on the SD-card. When the sample is taken, the data
logger goes into sleep-mode again. This is repeated, until the time has matched the Send interval.
So, in this example, this is 3 hours.
4. When Data Send interval is reached, the data logger will wake-up, and starts to send the previously
collected data (stored on the SD-card) to the server. So, in this example, every 10 minutes a sample
is taken, and every 3 hours, 18 samples are send.
Note: So, the data logger does not perform any averaging. Even if the sample interval is much faster than
the data log interval, only one sample is stored.
The use of the sample interval is for evaluating proper behavior of the system, while the USB is
connected. Because in that case, the sample interval is valid, and the user can observe the value’s
obtained from the sensor in real time. In this case, the user can evaluate these values every 5 seconds.
4.2 SDI-12
The ML-2012/13 is provided with an SDI-12 port. This port is connected to port 2 and is shared with the
normal RS232 operation. This means that the user has to select whether he wants to use RS232 or SDI-
12. When SDI-12 is selected, it acts like a SDI-12 recorder and its specific SDI-12 commands are
embedded in the driver of the input-sensor. So the user can easily select his sensor and specify its SDI-
12-adress. For more information see the description of you SDI-12 sensor.
4.2.1 SDI-12 Hardware
The SDI-12 standard is a very commonly used interface-standard in the USA. In Europe, it is rarely used.
The signal levels are quite different from those of RS232 and RS485. So, you cannot connect a SDI-12
sensor to a RS232 or RS485 port, it won’t work. The use of convertors between RS232/485 and SDI-12 is
discouraged, because of the high pricing of the convertors and the bad performance (see note).
4.2.2 SDI-12 Wiring
The SDI-12 electrical interface uses the SDI-12 bus to transmit serial data between SDI-12
data recorders and sensors. The SDI-12 bus is the cable that connects multiple SDI-12 devices.
This is a cable with three conductors:
1) a serial data line, 2) a ground line and 3) a 12VDC line

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 18
The wiring length between a sensor and the data-recorder must not exceed 60 meters. The maximum
number of sensor connected to a SDI-12 bus is limited to 10. The ML2011 is protected against transients
on the SDI-12 bus.
4.2.3 SDI-12 Baud Rate and Frame Format
The baud rate for SDI-12 is 1200. Frame format is as follows:
1 start bit
7 data bits, least significant bit transmitted first
1 parity bit, even parity
1 stop bit
Note:
SDI-12 is a half-duplex protocol, so the data-recorder has to switch between transmitting and receiving. A
convertor from RS232 SDI-12, must perform this task. However, it is not aware of the exact timing of
the protocol. Therefore it uses fixed (or configurable) delays to switch between Tx and Rx. After each byte
send by the convertor, it waits, during the fixed delay, for another character, and if it doesn’t arrive, it
switches to Rx. The intelligence needed to perform these tasks is mostly done by a microcontroller inside
the convertor, that’s the main reason for its high pricing. This method is doing the job for most cases, but
it is not as good as a real SDI-12 port. The real SDI-12 port is aware of the exact protocol-timings and
after the last character it switches to RX-mode immediately, without the delay. Therefore no replies are
missing. Your ML-2012/13 has a true SDI-12 port.
For more information on the SDI-12 protocol: see www.sdi-12.org
4.3 RS232
Your ML-2012/13 comes with 2 RS232 ports, capable of baud rates of up to 115200 bps (230400 bps on
request). The ports are: port 1 and port 2. Port one is shared with the RS-485 port and port 2 is shared
with the SDI-12 port. The user can choose any combination he likes, as long as he is using only one at a
time. (e.g. you cannot share RS232 and RS485 one the same port). If a user needs RS232 and RS485
simultaneously, he needs to setup Port 2 also.
RS232 is a widely spread interface standard, which uses 3 wires (minimum) for data communication. It is
a so called asymmetric interface, that uses one wire for Tx, one for Rx and one for ground. It is called
asymmetrical, because it uses only one wire per signal. Therefore it’s susceptible for interference, and
hence, the maximum cable length is limited to 15meters.
Please keep in mind these limitation when you design your system.
RS232 is not a bus system, and therefore it is only allowed for one device to be connected to a RS232
port. So, the maximum number of serial devices to connect to your ML-2012/13 is 2. RS232 sensors
should be connected to the data logger with their signals crossed. That is Rx Tx.
We strongly recommend using RS485 instead of RS232, when cable length exceeds the 15m.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 19
4.4 RS485
RS485 is a serial bus-system, which uses 3 wires for its communication. It uses a “differential balanced
line”, which can span relatively large distances (up to 4000 feet (1200 m)). A rule of thumb is that the
speed in bit/s multiplied by the length in meters should not exceed 10
8
. Thus a 50 meter cable should not
signal faster than 2 Mbit/s.
Instead of RS232, RS485 is capable of communicating with more than one device. After all, it is a bus-
system.
RS485 sensors are called “slaves” and must have their unique address. The ML-2012/13 acts as a
master and retrieves the information from the slaves. Only one slave can respond to the requests of the
master at a time.
To set up your RS485 sensor for use with the ML-2012/13, make sure that the address is programmed
correctly, and that the sensor address is unique.
Figure 1: RS485 Wiring
RS485 is often used with MODBUS/RTU-sensors, and is less susceptible for Electrical interference than
RS232.
Your ML-2012/13 has one RS485 port which is capable of driving multiple sensors (maximum amount of
sensors depends on specs from the manufacturer of the sensor, a practical figure is 10. The maximum
amount of slaves, defined by EIA/RS485 is 32). For the exact number of sensors you can connect to your
ML-2012/13 see chapter Firmware Driver limitations
We recommend using twisted pair cable to connect to the sensors.

USER MANUAL TYPE ML-2012/13
Manufacturers of low power instruments page 20
4.5 Analog Inputs (4..20mA)
The ML-2012/13 is equipped with four analog mA 12 bits AD-Conversion inputs The input signal must be
a 4..20 mA current loop. The impedance of the system is 150 ohms.
4.5.1 Loop Powered Devices
Some devices don’t need a power supply, but take their power from the current loop. But the primary
circuit of the ML-2012/13 does NOT provide power for this. In this case, you need the power switch to
provide the energy for the current-loop. Consult the manual of the loop-powered device you like to
connect, and use the positive side of the power switch for the power supply. In most cases the ML-
2012/13 is connected to a device with an active output signal, so there will be no problems connecting it.
If you have questions about interfacing your device with the ML-2012/13, contact your YDOC-dealer.
4.6 Analog Differential Inputs (ML-2013 only)
The ML-2013 Data logger has, besides the four 12 bits analog current inputs, also two additional
Differential 16 bits voltage inputs. These inputs are very sensitive and particularly suitable for measuring
signals from load cells.
4.6.1 Differential input ports theory of operation
Differential inputs are very convenient for measuring differential or floating signals. The performance of a
differential input is much better than a normal, single ended one, especially with small mV signals.
Therefore, the differential inputs on the ML-2013 are very suitable for measuring load cells, pyranometers
and other low-level mV output sensors. A differential input consists of a negative (-) and a positive (+)
input. The voltage difference between these two inputs is the signal to be measured.
4.6.2 Common mode noise rejection
One of the major advantages over a single ended input is the common mode noise rejection. It “removes”
practically all noise that is present on the input signal. Especially with long cables, noise is always present
on the leads. Since the input acts like a differential amplifier, the noise on the negative input is subtracted
from the noise on the positive input. What is left is the sensor-signal.
4.6.3 Using Load Cells With the ML-2013
The ML2013 is very suitable for connecting load cells and other resistive elements. A load cell acts as a
bridge of Wheatstone and is a very sensitive and precise passive component.