Frequently Asked Questions:

Squirrels and Darca

• What are Darca's System Requirements?
• Why can't I establish a connection to the Squirrel from Darca?
• How do I configure a Squirrel Modem?
• How do I use AT Commands to set up a modem?
• I have problem establishing a connection with a logger attached to a GSM modem.
• I have problems with connection reliability when using Darca with an instrument attached to a GSM modem.
• What operations are not possible with Eltek Squirrels?
• The help does not work in Windows Vista.

Q. What are Darca's System Requirements?

• PC running Windows 98/ME/NT/2000/XP/Vista
• 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)
• Windows compatible modem (if remote connection to Squirrel is desired)
• 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:
   
   

   or

   AT&W AT&W1

   [Enter]. [Enter].

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

Q. The help does not work in Windows Vista.

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

If you have an FAQ that you would like share with others in this section then please contact us at sales@eltekdataloggers.co.uk.