This is a problem that customers sometimes come across when attempting to generate messages or transform messages. The values which are being assigned by the customer to the MSH identity fields always default to a fixed value.

For instance, if you were attempting to set these fields in a table using C++ code you might have the following:

Msg.EXAMPLEHeader(0).SetMessageType("T02");
Msg.EXAMPLEHeader(0).SetMessageTypeEventCode("EXAMPLE");

This is setting fields in the table mapping:

Instead of the expected generated message:

MSH|^~\&|SOMECOMPANY|SOMECOMPANY|ADMIN||||T02^EXAMPLE|1234544444444101292002185500003|P|2.5|

You instead get:

MSH|^~\&|SOMECOMPANY|SOMECOMPANY|ADMIN||||EXAMPLE^EXAMPLE|1234544444444101292002185500003|P|2.5|

This occurs because the last step of message generation that Chameleon follows is to populate the fields listed in the Message Identity.

The resolution to this problem is to remove the message identity rows that are overwriting the values that you wish to set dynamically.

Therefore the original message identity is shown below:

Then by removing the rows in the message identity, the resulting table looks like this:

For more information, see Manually Defining the Message Identity.

	It is much better to have separate vmd files for parsing and message generation. Since the identification tables are useful only when parsing a message, a vmd file used for generating messages does not need them since alternative techniques like using python scripting or mapping can be used to set these values.