Home » Categories » Protocols » Modbus

My RX light is on solid, what might that indicate?
Article Number: 561 | Rating: Unrated | Last Updated: Fri, Jul 17, 2015 at 10:32 PM
If the RX light is on solid on your modbus serial port and:

The port is in RS485 mode- This is usually indicative of polarity being reversed (ie. positive is connected to negative instead of positive to positive). Try swapping the wiring to pins 1 and 8 on our port.

The port is in RS232 mode- This suggests that a constant electrical signal is hitting our receive pin which should never occur during normal operation. We have seen this on occasion with customer USB to serial converters which are not set up correctly, we strongly recommend trouble shooting your USB to serial converter if this is the case. If there is no converter involved, we recommend verifying the wire connected to our RX pin is connected to the correct pin on the other device.

If none of these common causes seem to be causing your RX to be on solid, please call Prosoft Technical Support to trouble shoot your issue further.
Custom Fields
    Posted by: Administrator - Fri, Jul 17, 2015 at 3:37 PM This article has been viewed 7778 times.
    Filed Under: Modbus
    Attachments (0) Attachments
    There are no attachments for this article.
    Comments Comments
    There are no comments for this article. Be the first to post a comment.
    Icon Add Comment
    Name
    Email (Required, but not published)
    Comment
    Security Code Security Code
     
    Related Articles RSS Feed
    Why is the bit or coil level data incorrect?
    Viewed 1 times since Tue, Nov 28, 2006
    I have a ProSoft Modbus Master solution and would like to know, is the Slave Status List the best place to monitor for communications health of the network?
    Viewed 1 times since Tue, Mar 18, 2008
    What Modbus address would we need to put into the MODSIM32 simulator if we specified on the MVI56-MCM device address to 8680HEX (-31104 decimal) when the MVI56-mcm is the slave?
    Viewed 1 times since Tue, Nov 28, 2006
    I have multiple Modbus masters that need to communicate with 1 or more Modbus serial (RTU) slave devices. What product should be used??
    Viewed 1 times since Tue, Jan 23, 2007
    Why are my PLX gateway modbus serial commands not executing despite being enabled?
    Viewed 1 times since Wed, Aug 12, 2015
    How do you detect the individual Slave failure?
    Viewed 1 times since Wed, Nov 29, 2006
    Can Modbus support redundant masters?
    Viewed 1 times since Tue, Nov 28, 2006
    How do I read/write Modbus binary data?
    Viewed 1 times since Wed, Nov 29, 2006
    How can I detect the feedback status of individual command successful or failed?
    Viewed 1 times since Wed, Nov 29, 2006
    What are the causes of a -11 error code using a ProSoft Modbus product?
    Viewed 1 times since Mon, May 17, 2010
    • Icon SubscriberSubscribe to Article
    • Icon PrinterPrint Article
    • Icon EmailEmail Article to Friend
    • Icon PDFExport to PDF
    • Icon MS-WordExport to MS Word
    • Icon TwitterTweet This Article
    • Icon DiggDigg It
    • Icon StumbleuponStumble Upon
    • Icon de.icio.usDel.icio.us
    Article Rating (No Votes)
    Rate this article
    Powered by PHPKB Knowledge Base Software