You run ComIML and choose to Add the Serial Instrument Handler. You receive an error saying "Empty file - replace with your own IMD file". You need to go back to ComDebug and save a Windmill device.

When you press Run in ComDebug you see the data correctly, but Logger or DDE Panel gives error 114. This indicates that Windmill might not have received a reply from the instrument, or that new data isn't available.

In ComDebug go to the Instrument Timing box and make sure that:

1. The TimeOut is between five and ten times the normal response time. If you don't know the response time, 5000 milliseconds should be adequate.
2. For instruments that continually send data, make sure the Data Persistence and Timeout are both longer than the rate at which the instrument sends messages and that you have chosen to read in the background.
3. For instruments being read in the background that need a prompt to send data, make sure that the Data Persistence is longer than the sampling rate. If you are logging data every second, for example, set the data persistence to 2 seconds. See the ComDebug Help for more details.
4. For instruments being read directly, set the Data Persistence Time to less than the rate at which you want to read data.
5. If using a USB-Serial converter, and in ComDebug have chosen to "read in background", make sure that your converter is continually providing data, and not buffering it. Depending on your converter:
   1. Set the lowest latency possible
   2. Set the lowest USB Transfer sizes possible
   3. Set fast read and writes
   To do this you may need to use the converter's utility program, or to go through Windows Control Panel. Open Control panel then choose device manager, Ports (COM), your USB-to-serial converter. Right click and select Properties. Choose the Port settings tab then the Advanced button.
   
6. For more information on the problem, whilst Logger or DDE Panel is running open ComDebug and view the Windmill Debug Screen. See below for details.

This screen displays debug messages from ComIML. To use the screen, first run a Windmill application such as DDE Panel or Logger. This will automatically start the ComIML handler and it will start sending out debug messages. Now start ComDebug and from the opening window click on Windmill Debug Screen. Messages will be displayed. You can click on Pause to stop the scrolling in order to examine the messages in detail.

Each Line starts with a number. This is a count of Milliseconds from the start of the Serial Message. It enables you see the time delays in getting a response from the instrument. A series of messages are supplied:

0 Start of Message Name

This is sent when ComIML starts to implement a message.

Send String

Sent when ComIML transmits a Prompt or Acknowledgement string. Non print characters are shown as < 123 >.

Start of Parse Attempt

ComIML is starting its attempt to parse the reply message. Timeout measurement starts from here.

Channel + Num + Value

The value extracted by the parse.

Parse OK

The full parse string has been implemented on the Reply Message.

Parse Timeout

The Timeout value has been exceeded before a Reply satisfying the Parse has been received. To change the Timeout, from the Main Menu select Edit the Instrument Timings.

Reply

The Reply string that was available when the parse terminated.

Channel + Num + Read

Windmill caused a full reading of this channel.

Channel + Num + Persist

Windmill read the stored value of this channel because the persistence time had not yet expired.

Flush Serial Buffer

Before ComIML starts a new message it reads and discards any bytes remaining in the serial buffer. These are displayed. No message is displayed if there are no discarded bytes.

Start of Wait Command

Some instruments can become overloaded if instructions arrive too quickly. To prevent this you can tell ComIML to wait for the length of the Instrument Idle or Wait Time. The end of the wait is indicated by the next action specified by the message.

Differences between Direct and Background readings (set in ComDebug's Instrument Timings)

When a direct reading is being made, Windmill waits for the reply so the process continues until the reply is available or a Timeout occurs. In Background mode ComIML does not wait for replies to be received. Instead it allows other messages to be implemented (on different COM ports) and also services requests by Windmill. Whenever it returns to a Background reply it makes a fresh attempt to parse it. This means that you will see the early channels parsed several times before finally a complete parse is obtained.

In Background mode the idle time delay is enforced between the end of one read of the module and the start of the next. This appears as a Wait message.