MODBUS and a Gas Micro corrector from Galvanic Applied Sciences Inc.

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Thread Starter

Dean Schneider

We are experiencing problems when tring to read data from MODBUS registers in a Gas Micro corrector from Galvanic Applied Sciences Inc.
We always seem to get the CRC error when reading data from the registers. The connection to the device is fine. If we try to poll a non-existent address we get an Illegal Data address error or a time out error. If we use an existing address we get the CRC error. Has anyone else ran into problems with MODBUS and the Gas Micro device?
 
If this is via an RS485 link there may be a timing issue. Such as, the slave keying down its transmitter before the last CRC character has cleared the Tx driver. You may have some timers to fine tune the problem away. In the old UART days this problem was common and the solution was to tack on one sacrificial character after the last CRC byte.
 
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