Julabo labview driver serial communication problems

[dexterpoet]

Hi All,

I am trying to communicate with a Julabo heater controller via an RS485 serial port using LabVIEW. There is a LabVIEW driver that can be found at http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=D1216BF0E8613C89E0440021287E65... . I am using a USB to serial converter provided by kksystems http://www.aa-kkemail.co.uk/kk-files/usb485.pdf and I have wired a patch cable to match the RS485 connection on page 79 of the Juabo manual (attaached) to the RS485 2-wire connection for the USB to Serial converter, and I keep getting this error, "Error - 1073807252: Overrun error". Can anyone please tell me what I need to do to resolve this?

[Dennis_Knutson]

The error indicates that the read is not happening fast enough. Data is still in the buffer when the instrument transmits more. You can increase the bigger size but that usually just postpones the problem. The driver is unsupported so you may have to debug the problem yourself.

[dexterpoet]

Hi Dennis_Knutson

I have gone to my device manager>USB Serial COM port>Port Settings>Advanced>Latency TImer and increased the Latency TImer to 255ms and I don't have that error again. However, I have a new error, "Error -1073807339": TImeout expired before operation completed, in the following path "VISA Read in JULABO DeviceDriver.lvlib:Read from COM Port.vi->JULABO DeviceDriver.lvlib:Query Instrument.vi->JULABO DeviceDriver.lvlib:Initialize.vi->My VI". How do I now resolve this?

[Dennis_Knutson]

I don't know since I don't have the instrument and won't download the driver. Look to see what the VI is doing and try the same command in MAX.

I would have thought that increasing the latency would make the communication worse.

[TDiana]

Hello dexterpoet,

could you solve the mentioned problem?

Greetings Diana