Since ESL is using the capabilities of the emulation software that you have chosen, it is necessary to verify that you have loaded this software and that there is a working connection. An easy way to verify this connection is with the Esl Fields Utility. The Esl Fields Utility is written in ESL so communicates with the host exactly same way as your ESL application; therefore, if this utility works, it is likely that your environment is set up properly. By using the Esl Fields Utility to test the connection, you can avoid other complications that might be introduced in writing an ESL program. If the Esl Fields Utility fails, then you should recheck the conditions for loading the emulator.

After you have established a working connection, the Esl Fields Utility should work as expected. You can switch from the emulator and see a host screen. If you have established a connection and you are still experiencing problems, verify that you are using a supported emulator with a supported HLLAPI, and that you have followed the configuration requirements stated earlier in this section.

If you start an application before loading the emulator, calls to ECS subroutines fail and generate an error message.

If this occurs:

•Use the invoke command to start the emulator.

•Once the emulator is loaded, use the EcsReStart routine to restart the ESLCMSRV stimulus library.

•If the emulator is still loading, the EcsReStart routine will set the integer error level parameter to 9, "Cannot initialize", in which case, your application should wait a short period before retrying the EcsReStart routine again.