Home > Support and Service


Link Title Code
{Link} {Title} {Code}
Title Code Link
Darca Software TD1030
Darca Heritage V1 Software TD1031 PDF
Darca Heritage V2 Software TD1095 PDF
Darca Secure Software TD1115 PDF
GenII Heritage Monitoring And Analysis TD1100 PDF
Online Tools TD1118 PDF
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{Link} {Title} {Code}
Title Code Link
1000 Series Squirrel TD1010 PDF
450/850 Series Squirrels TD1090 PDF
651 Energy Audit Squirrel TD1114 PDF
Energy Series Squirrels TD1040 PDF
Energy Monitoring Squirrels TD1125 PDF
RC250 Receiver TD1081 PDF
RX250DAC - Receiver / Logger TD1075 PDF
WSR - Wireless Sensor Receiver TD1082 PDF
Link Title Code
{Link} {Title} {Code}
Title Code  
GS41AV - Air velocity measurement TD1111 PDF
GD40A - Energy monitoring using CTs TD1102 PDF
GD43 - Temp/RH & CO2 transmitter (inputs for external sensors) TD1084 PDF
GD47 / GW47 / GD47A - Air quality transmitter (built-in sensors for temp/RH and CO2) TD1096 PDF
GC60F - Flood sensing transmitter TD1087 PDF
GC62 with people counter sensor TD1088 PDF
GD62/7/8 - Energy monitoring with pulse transmitters TD1108 PDF
GD72E - UV & visible light transmitter TD1093 PDF
GD84 - Differential pressure transmitter TD1080 PDF
GD93A - MBus transmitter for use with Landis & Gyr Heatmeters TD1116 PDF
GD90A - Energy monitoring system TD1097 PDF
GD900A - Multidrop energy monitoring system TD1107 PDF
OD41A - Pyranometer transmitter in weatherproof enclosure TD1109 PDF
TMET - Weather monitoring system TD1101 PDF
OD04 - External thermistor transmitter in weatherproof enclosure TD1122 PDF
OD43JS - Mini weather station with GD43JS transmitter TD1113 PDF
OD13E and OD14E - External RH and temperature transmitter in weatherproof enclosure TD1128 PDF
ELCC - AC Transducer for GC60, GD24, GD34 TD1091 PDF
EC Series transmitters TD1129 PDF
Link Title Code
{Link} {Title} {Code}
Title Code Link
GenII Telemetry System TD1079 PDF
Energy Monitoring System (GD-90A) TD1097 PDF
Multidrop Energy Monitoring System (GD-900A) TD1107 PDF
Compost Monitoring System TD1110 PDF
Conservation Research TD1117 PDF
Built Environment System TD1119 PDF
Tilt and crack monitoring with GenII Transmitters TD1120 PDF

User Instructions

Link Title Code
{Link} {Title} {Code}
Title Code Link
Moxa NPort 5110 setup TU1029 PDF
RP250GD Repeater TU1007 PDF
RX250AL and GenII Transmitters Quick Start TU1008 PDF
WSR Wireless sensor receiver TU1006 PDF
Link Title Code
{Link} {Title} {Code}
Title Code Link
GC62 Pulse transmitter TU1003 PDF
GenII quick start TU1008 PDF
GS41A Pyranometer transmitter TU1010 PDF
GC62A Pulse transmitter TU1011 PDF
GS42 / GS42E Voltage / current transmitters TU1019 PDF
GS44 / GS44E Voltage / current transmitters TU1020 PDF
GS42H / GS44H Bipolar Voltage for Hukseflux Heatplate TU1055 PDF
GC60Y Enhanced count transmitter TU1021 PDF
GD90A Energy monitoring transmitter (NDRail350) TU1023 PDF
GS42AVE/GS44AVE Averaging transmitter TU1026 PDF
TMET Weather transmitter (with WXT520 sensor) TU1032 PDF
TMET Weather transmitter (with WXT530 sensor) TU1073 PDF
LS50 with GenII transmitters TU1033 PDF
GC60 State inputs transmitter TU1035 PDF
GD68 Pulse input transmitter TU1036 PDF
GW47 CO2, RH and temperature transmitter TU1037 PDF
GD47A CO2, RH and temp transmitter with Alkaline batteries TU1070 PDF
GD40A Current (CT) transmitter TU1038 PDF
GD43JA used with Kipp and Zonen NRLite net radiometer TU1041 PDF
GD900A Energy monitoring transmitter (multi NDRail350) TU1043 PDF
GD93A used with T230 TU1045 PDF
GD32ALS / GD34ALS transmitters TU1047 PDF
GS41AV Air velocity transmitter TU1049 PDF
GD900F Energy monitoring transmitter (Smartrail 835mV) TU1050 PDF
GD24ALDM / GD34ALDM temperature transmitters with audible and visual alarm TU1057 PDF
GD43E RH/temp and voltage/current transmitter TU1059 PDF
OD17EE Customised RH, temp and CO2 battery powered transmitter TU1061 PDF
OD18W wind speed/direction transmitter TU1064 PDF
EP85 customised K type thermocouple and differential pressure transmitter TU1069 PDF
Link Title Code
{Link} {Title} {Code}
Title Code Link
RHT10D digital RH and temperature probe TU1001
RHT10E digital RH and temperature probe TU1056 PDF
Eltek Squirrels with Vaisala WXT and WMT weather sensors TU1022 PDF
EE08 RHT probe with GenII transmitters TU1024 PDF
Rotronic HC2-S3 probe with GenII transmitters TU1025 PDF
LS50 with GenII transmitters TU1033 PDF
LS70 with GenII transmitters TU1034 PDF
Link Title Code
{Link} {Title} {Code}
Title Code Link
RX250AL and GenII transmitters quick start TU1008 PDF
GSMSQ modem kit TU1016 PDF
GSMPC modem kit TU1017 PDF
GSMDH modem kit TU1065 PDF
Moxa NPort 5110 setup TU1029 PDF


Link Title Code
PDF Darca Plus TM1020GB
PDF Darca Heritage Version 1 TM1030GB
PDF Darca Secure TM1031GB
PDF Darca Heritage Version 2.0 TM1032GB
PDF Darca Heritage Version 2.1 TM1038GB
PDF 450/850/1000 Series and GenII Loggers - German TM1033DE
PDF 450/850/1000 Series and GenII Loggers - French TM1033FR
PDF 450/850/1000 Series Squirrel - English (newer version, updated 12-11-13) TM1034GB
PDF RX250AL and GenII Manual TM1035GB
PDF RC250 Receiver System TM1039

Technical Notes

Link Title Code
PDF Adding transmitters to a remote system
Web page Online radio coverage survey tutorial TN125

Product Gallery

Download a zipfile containing high-res images of the full Eltek product range.

Frequently Asked Questions:

Problem: My PC can no longer communicate with the logger since I upgraded to Windows 10

Users who have upgraded to Windows 10 and are using older RS232/USB adaptors supplied by Eltek may find that the unit RS232/USB does not function after the upgrade. Older RS232/USB adaptors cannot be readily physically identified as different from later devices, but their status can be checked within Windows 10.

To check the operational status of the adaptor within windows, type Device Manager into the Windows 10 search box and click Device Manager (Control Panel).

Eltek's RS232/USB adaptor is identified under the Ports section as Prolific USB-to-Serial Comm Port. Older (non functioning) adapters will have a yellow triangular symbol next to them:

Device Manager

Right clicking the older, non-functional device and choosing Properties will show the following status:

Device Manager Properties

Eltek's recommended fix is to obtain a new, guaranteed device from Eltek. This can be supplied from stock at GBP15.00 including next day carriage but excluding VAT. Payment can be made by card.

Alternatively, for users with a high level of technical knowledge, the following link can be reviewed:

Please note: Eltek does not offer technical support relating to this link.

Q. What is the best way to contact a logger remotely using GSM?

On the logger side
Use the Eltek GSMSQ kit. This kit contains a GSM modem which arrives configured for use with Eltek telemetry or conventional Squirrel 1000 series data loggers. No adjustment is necessary. Packed in the box is the following:

  • Wavecom Extend modem
  • Mounting tabs
  • Logger to modem lead (type GSM-mdm-com2X)
  • Antenna with 1.8m lead
  • SMA connector
  • User instructions

A SIM is NOT included. The SIM can be a low cost contract SIM as data is via the voice channel of the GSM network.

The GSM modem is powered by the logger external supply. Therefore an external supply must be used with the logger, e.g. the MP12U power supply. If the external power fails the logger will continue to function but GSM functionality will be lost.

The GSM modem is used to deliver text messages, contact the logger, make logger set-up changes and download data from the logger memory.

To use the GSM modem for remote access via the GSM network and/or Alarm SMS texting, plug the supplied lead (type GSM-mdm-com2X) into the GSM modem and connect the other end to the "output" socket of the logger.

On the PC side
It is recommended that the PC is equipped with a dedicated GSM modem (e.g. Eltek's GSMPC), which means that only the voice number is required for communication. If the PC is connected to the mobile network via a land line, an analog data number must be used. These data numbers are allocated by the SIM provider and are often difficult to obtain. When the PC is equipped with a dedicated GSM modem such as the GSMPC kit, however, then the remote logger GSM and PC GSM are communicating directly. This avoids the need for an analog data number altogether.

The Eltek GSMPC kit consists of the following:

  • Wavecom Xtend modem
  • Antenna
  • Modem to PC serial lead (type LC-PC/MDM)
  • AC to 12V DC power supply (type MPGSMextend)

A SIM is not included. The SIM can be a low cost contract SIM as data is via the voice channel of the GSM network.

Following the user instructions provided with the kit will quickly get you going.

Q. What are Darca's System Requirements?

  • PC running Windows 98/ME/NT/2000/XP/Vista/7
  • CDROM drive (for installation)
  • 16Mb RAM
  • 8Mb free hard disk space for program
  • Additional hard disk space for data
  • VGA (or better) display
  • One unused serial port (or USB slot if used with a USB to Serial Converter)
  • LC68 cable
  • Eltek 1000 Series / RX250AL Squirrel

Q. Why can't I establish a connection to the Squirrel from Darca?

There are a number of reasons that this problem could occur:

  • The Squirrel does not have a power source (either batteries in the Squirrel’s battery compartment or an external mains power supply (MP12U).
  • The Squirrel is not asleep. To correct this, select OUTPUT mode and wait 3 seconds for the Squirrel’s display to go blank.
  • You are trying to connect to a networking Squirrel but have not selected the ‘Networked Squirrel’ option in the Settings|Communications dialog.

If you are using a Modem connection:

  • The Modem is not connected to your PC.
  • The Modem is not connected to your phone line.
  • The Squirrel is not connected to the remote modem by an LC69 cable.
  • Your Modem is not installed in Windows properly. Check the ‘Modems’ section of Control Panel.
  • The remote Modem has not been configured correctly.

If you are using a Direct connection:

  • The Squirrel is not connected to your PC by an LC68 cable.
  • The LC68 cable is plugged into the wrong COM port – check your settings in the Settings|Communications dialog.
  • The baud rate is set wrong in the Settings|Communications dialog. All 1000 series / RX250AL Squirrels manufactured since the year 2000 will communicate at 38400 baud or slower.

Q. How do I configure a Squirrel Modem?

It is very important to correctly configure the modem that is going to be connected to the Squirrel. Most problems involving Darca and modems can usually be traced to the Squirrel’s modem not being set up.

Connect the modem directly to the computer using the RS 232 port, which is usually at the back of your computer and labeled Comm 1 or Comm 2. To configure this modem you will need to use a simple terminal emulation program such as Windows Terminal. You can then send AT commands to the modem in order to configure it in the way you require. When using such a program, be sure to set it to the correct Comm port, and to the baud rate which you will be using once the modem is connected to the Squirrel.

Unfortunately, as each manufacturer has their own version of the AT command set, this help file cannot list the necessary commands for your particular modem. However, most modern modems have sensible defaults and clear instruction manuals.

IMPORTANT: These guidelines assume that all the modem’s settings are the ‘factory defaults’. If this modem is brand new, then this is probably so. If not, look up how to restore the defaults in the modem’s handbook. On some modems, some of the settings described below may require a tiny DIP-switch to be set, rather than an AT command to be sent. Occasionally, a manufacturer will put more than one ‘factory default’ profile in the modem. In this case, make sure that the profile has auto-baud rate negotiation and hardware (not software) flow control. N.B. references to RTS/CTS mean hardware flow control, which is appropriate. References to XON/XOFF mean software flow control, which would be unsuitable.

Q. How do I use AT Commands to set up a modem?

These instructions assume you have a new, high-speed modem with a data input buffer of at least 1k. Most modern modems conform to this requirement.

  1. Ensure that the baud rate in the terminal emulator you are using is set to a baud rate that is compatible with the Squirrel. This is typically 19200 baud.
  2. Leave the modem’s hardware flow control enabled. The Squirrel cannot use flow control, but the data packets that it sends are so small they will fit into the modem’s input buffer without over-filling it and causing the transmission of flow control signals. The error correction and data compression can also be left enabled.
  3. Since Darca will ultimately be dialing this modem up, it needs to be told to automatically answer any calls. Thankfully, this is always done with a particular S-register (S0). So, to set the modem to answer after 2 rings, the following should be sent:

    0 ATS0=2 [Enter].

    Should you require the modem to answer after 4 rings, substitute the 2 for a 4. Some modems require a DIP-switch to be set to enable auto answering.
  4. This new configuration must be saved in the modem so that whenever the power to the modem is turned on this new profile will be used. It is important to make sure that the baud rate at which you send the following command is compatible with your Squirrel (i.e. 19200 baud or slower for 1000 Series / RX250AL Squirrels), as you are also storing this baud rate along with the settings that have changed in points 2 & 3. The exact AT command will depend on your modem, but is typically:


Q. I have problem establishing a connection with a logger attached to a GSM modem.

A. Make sure the communication baud rate is set to 9600 in Darca. At other speeds the logger may not 'wake up' reliably.

Q. I have problems with connection reliability when using Darca with an instrument attached to a GSM modem.

A. Due to the nature of GSM you are more likely to get checksum errors on data from and to the logger. To prevent Darca from 'giving up' the connection, with an error like 'the logger could not be woken' you can increase the numbers of times Darca retries to 'wake up' the logger and the number of times it will retry a command to the logger. To do this go to settings then preferences and select the timing tab. Increase the wake up retries to 25 and the command retries to 10. This is particularly important if the logger is also scanning or logging the inputs very frequently.

Q. What operations are not possible with Eltek Squirrels?

  • Clear the memory while logging is in progress
  • Start logging when the memory is full
  • Start logging if no channels have been selected
  • Perform multiple runs if memory is in continuous mode
  • Reset pulse count while logging is in progress
  • Change date and time while logging
  • Change start date and time while logging
  • Change log and sample intervals while logging

It is not possible to change the following either when there are readings stored in memory or when logging is in progress:

  • Log mode
  • External trigger mode
  • Memory mode
  • Channel set up and ranges
  • Engineering unit ranges
  • Memory size
  • Language type
  • Sensor switch on time
  • Date format
  • Filter frequency

How does the logger store data from pulse transmitters?

  • Each pulse transmitter contains a counter which counts the pulses from a connected sensor. This counter rolls over when it reaches its maximum value.
  • During each logging interval, the logger will receive a number of transmissions of this counter value from each pulse transmitter. These will occur at random times in order to minimise signal clashes.
  • When the logger reaches the end of the logging interval, it looks at the last counter value it received from a transmitter. It compares this with the counter value from the previous logging interval and stores the difference of the two values. If the counter has rolled over during the logging interval, it will see the newer value as lower than the previous value and will take this into account when calculcating the value to store.
  • The value of measured pulses that the logger stores is therefore never tied to a strict time interval as the time between transmissions is random. Over longer periods of time, however, this fact becomes irrelevant.

Problem: The help does not work in Windows Vista / Windows 7.

A. Microsoft decided not to include the windows help system with Windows Vista or Windows 7 by default. Darca plus and Darca Lite currently use this form of help. You can install the help system via microsoft from the following location(s):

Windows Vista:

Windows 7:

Problem: The Tx interval on GenII transmitters resets to 5 seconds.

A bug can cause this problem if you attempt to set a local alarm on a transmitter that does not have the alarm hardware option. To cure the problem, use Tx setup to ensure all Hi and Lo alarms are set to 'Not Set'.

Which mathematical formulae can be used with Darca Heritage?

abs(x) Return absolute value
acos(x) Calculate arccosine
asin(x) Calculate arcsine
atan(x) Calculate arctangent
atan2(x, y) Calculate arctangent with two parameters to preserve quadrant angle
bessj(n, v) Bessel function of the first kind. n is order and v is input value.
bessy(n, v) Bessell function of the second kind. n is order and v is input value.
ceil(x) Find integer ceiling
cos(x) Calculate cosine
cosh(x) Calculate hyperbolic cosine
exp(x) Calculate exponential function: ex
floor(x) Calculate integer floor
hypot(a,b) Calculate hypotenuse of right triangle
log(x) Calculate natural logarithm
log10(x) Calculate base-10 logarithm
max(x, y) Return larger of two values
min(x, y) Return smaller of two values
rand(x) Get pseudorandom number between 0 and 1
sin(x) Calculate sine
sinh(x) Calculate hyperbolic sine
sqrt(x) Find square root
srand(x) Initialize pseudorandom series
tan(x) Calculate tangent
tanh(x) Calculate hyperbolic tangent

If you have an FAQ that you would like share with others in this section then please contact us at

After Sales Service

Eltek's extensive After-Sales Service package includes:


1000 Series Squirrel data loggers are guaranteed for three years against faulty materials or workmanship.

The guarantee given for equipment supplied by us, but not manufactured by us (this includes all sensors, whether built into probes or not) is limited to the guarantee given by the manufacturer of the particular product.

If repairs are carried out under guarantee, no charge is made for labour, materials, or return carriage.


Repairs are normally carried out within five working days of arrival at our facility in Cambridge or receipt of authorisation to repair. Spare parts and service manuals can be dispatched within two working days. Distributors of Eltek data loggers outside the UK may hold stocks of spare modules and most have their own service engineers and operate a similarly prompt repair service.

Installation and Commissioning

Eltek can provide installation and commissioning services for both data logger and telemetry applications.

Please contact Eltek for a detailed quotation.


Eltek can provide training to end users so that the actual users quickly become familiar with and competent in the use of Squirrel data loggers.

In addition to the use of the data logger itself there will be in-depth and hands-on use of the Darca software including use of the graphing (where applicable), data, setting up, and down loading tools.

Training is normally conducted at the customer's premises and usually takes about 3 hours.

Mileage and travel time is charged for plus 3 man hours at the standard labour rate.

Contact Eltek for a quotation.

Site Survey

This is normally only needed for telemetry systems. Before ordering a telemetry system it is important to identify any areas where radio coverage may not be good so that the system can be designed to work round them. The survey is conducted using radio, operating in the frequency band that the customer can actually use. This will reveal any need for devices such as repeaters or external antenna, making sure that the system supplied is appropriate for the site before installation.

Generally a half day to one day is required, dependent upon the size of the installation envisaged.

Mileage and travel time is charged for plus the number of man hours for the actual survey work plus one man hour for report preparation at the standard labour rate. A report is provided with findings, recommendations and alternatives if necessary.


Certificate of Conformity
A Certificate of Conformity (COC) is issued with every Eltek Squirrel data logger, or telemetry component to confirm that it has passed all the functional safety tests which check that it meets its specification, including the calibration process described below.

Initial Calibration
Every Squirrel is subject to a calibration procedure and heat soak test to ensure the stability and accuracy of the readings with changes in ambient temperature. The input values are provided by equipment with calibrations traceable to national standards.

Calibration Certification
Eltek can carry out an even more stringent calibration procedure and issue a calibration certificate at extra cost. The Squirrel is subjected to a second calibration in a temperature-controlled calibration laboratory. Each range is checked at five points, using equipment with calibrations traceable to national standard and a record is made of the results.

NAMAS Certification
Eltek can also quote for full NAMAS certification. This certification, similar to the stringent calibration noted above, is carried out by an independent calibration laboratory certified by the British National Measurement Accreditation Service (NAMAS). This certification process can include extra calibrations or tests if requested on the logger alone or together with sensors.

Please contact Eltek to discuss your requirement so that a detailed quotation can be prepared for you.