Crammed77
Member
I know, I know.. not another 1734-232ASC serial communications to printer topic!! I think I have a slightly different one here and I am hoping to gain some understanding of what is going on here. I have a printer installation here on site that works, and I thought it would be a piece of cake to duplicate the installation on another machine center. One is through DeviceNet Point I/O, the new one I planned on Ethernet Point I/O.
Working installation - (ControlLogix / DeviceNet)
1734-ADN with a 1734-232ASC card connected up to a printer. The printer talks Modbus RTU, but it is a custom format message that I send straight over to the printer out of the RS232 port. The printer does not use basic Modbus function codes. So I develop a message as per the user manual, in hexadecimal, send it to the printer over the serial port, and it prints what I want it to print!! Easy!! I did this job about 6 years ago and it has been working ever since.
Semi-Working installation - (ControlLogix / Ethernet I/O)
1734-AENT with a 1734-232ASC card connected up to a newer version of the same printer. This printer also talks Modbus RTU with the same message structure that I use above. When I send the msg to the printer, it freezes and reboots itself. I can send some messages to the printer that I get a valid response back from, but there are a few particular messages that reboot the printer.
This is what I have done to test out the new installation -
*Double check the format of the message to ensure that I have the correct format - All good according to the manuals and previous installation.
*Connect up my laptop and use RealTerm to diagnose the output of the ASCII card - The output message matches the format I am after.
*Try to send a different command message to the printer via the ASCII card - I can successfully send and receive data from the printer when interrogating the error status of the printer for example.
*Send the message that I want out of my laptop using RealTerm - The printer accepts the message and all is good. (this one really miffs me!!)
*Compare the output of the 1734-232ASC module with the output of my laptop using RealTerm - The serial string matches byte for byte.
*Contacted the supplier of the printer for their assistance - We are bouncing things back and forth, but the tech support is slow as they are on the other side of the world.
I read a lot about how the 1734-232ASC is not ModbusRTU, but I am using it else ware without a problem as just a 'serial string sender'.
I am wondering if maybe the 1734-232ASC card is putting out frame header information that I cannot see through RealTerm (or don't know how to), that is different than what ModbusRTU protocol is after on these printers?? The strings from both the 1734-232ASC module and the ones I am sending over RealTerm match when viewed in the terminal window.
By the way, I have these same type of printers talking on Modbus TCP Ethernet on yet another installation. For that one I am talking 1756-L62 to the printers through a Prosoft MVI56-GEC Generic ASCII Ethernet Interface Module. I was not able to use the Modbus purposed Prosoft MVI56-MNET because these printers use custom function codes that are not supported by the MNET card, and in such the header of the TCP Modbus message was all screwed up and the printer rejected the message. I basically use the GEC card to send out the whole string in the format expected by the printer.
I am probably missing something simple, but in the last few days of trying to test this out my head is getting sore and the frustration levels are starting to peak!! Thanks in advance.
Working installation - (ControlLogix / DeviceNet)
1734-ADN with a 1734-232ASC card connected up to a printer. The printer talks Modbus RTU, but it is a custom format message that I send straight over to the printer out of the RS232 port. The printer does not use basic Modbus function codes. So I develop a message as per the user manual, in hexadecimal, send it to the printer over the serial port, and it prints what I want it to print!! Easy!! I did this job about 6 years ago and it has been working ever since.
Semi-Working installation - (ControlLogix / Ethernet I/O)
1734-AENT with a 1734-232ASC card connected up to a newer version of the same printer. This printer also talks Modbus RTU with the same message structure that I use above. When I send the msg to the printer, it freezes and reboots itself. I can send some messages to the printer that I get a valid response back from, but there are a few particular messages that reboot the printer.
This is what I have done to test out the new installation -
*Double check the format of the message to ensure that I have the correct format - All good according to the manuals and previous installation.
*Connect up my laptop and use RealTerm to diagnose the output of the ASCII card - The output message matches the format I am after.
*Try to send a different command message to the printer via the ASCII card - I can successfully send and receive data from the printer when interrogating the error status of the printer for example.
*Send the message that I want out of my laptop using RealTerm - The printer accepts the message and all is good. (this one really miffs me!!)
*Compare the output of the 1734-232ASC module with the output of my laptop using RealTerm - The serial string matches byte for byte.
*Contacted the supplier of the printer for their assistance - We are bouncing things back and forth, but the tech support is slow as they are on the other side of the world.
I read a lot about how the 1734-232ASC is not ModbusRTU, but I am using it else ware without a problem as just a 'serial string sender'.
I am wondering if maybe the 1734-232ASC card is putting out frame header information that I cannot see through RealTerm (or don't know how to), that is different than what ModbusRTU protocol is after on these printers?? The strings from both the 1734-232ASC module and the ones I am sending over RealTerm match when viewed in the terminal window.
By the way, I have these same type of printers talking on Modbus TCP Ethernet on yet another installation. For that one I am talking 1756-L62 to the printers through a Prosoft MVI56-GEC Generic ASCII Ethernet Interface Module. I was not able to use the Modbus purposed Prosoft MVI56-MNET because these printers use custom function codes that are not supported by the MNET card, and in such the header of the TCP Modbus message was all screwed up and the printer rejected the message. I basically use the GEC card to send out the whole string in the format expected by the printer.
I am probably missing something simple, but in the last few days of trying to test this out my head is getting sore and the frustration levels are starting to peak!! Thanks in advance.