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Serial communication problem with Jazz JZ10-11-R16

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as this is my first post I want to say hello to everybody in this forum. I am facing a problem trying to communicate with a JZ-11 via the serial port.


My environment: Linux box (raspberry pi) connected to Jazz via USB program cable (which is working fine as I can communicate with this cable on a Win 7 64 Bit box), serial line parameters are

9600 baud, 8bit, No parity, 1 stop bit. I am sending an ASCII-based string to the Jazz to read the RC-clock value as described in http://www.unitronics.com/docs/technical-library/com.pdf?sfvrsn=0. For communcation I am using a serial class library for Python (pySerial). The string I send is "/00RCF5\r" which correspondes to the "Read RTC" command (page 6 in the Unitronics document).


Unfortunately when waiting for a reply from the Jazz I am waiting forever.


Does anybody have an idea how I can solve this issue?


Thanks in advance,




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  • 2 weeks later...

Hi Wachovius,

You can try and connect the Raspberry Pi to a PC and use a serial terminal to monitor exactly what signal the PC receives.

My assumption regarding this is that the Raspberry Pi is using a TTL serial communication and not RS232 serial communication layer.

You can find more about the differences between these two here.


Another thing: the standard communication parameters of the Jazz are as follows:

Baud rate 9600

Parity: Even

Stop Bits 1

Data Bits 7

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  • 1 month later...

Hi i am new using  jazz oplc i am tryng to program a jz10-11-un20 and it is giving me problema with comunication i am using a MJ20-PRG with MJ20-CB200 cable MJ10-22-CS10 and all of these join to mi computer wit a Logitech USB to serial DB9 converter   the problen is the software U90 LADER after i configure all the com parameters tels me cant find com port 1 iven if i change the com port in the computer and the software to any other com port i was wanderinf if the Logitech convertion usb to rs232 is not adecuate to do the job


Tanks in advance for your help

PD sorry about my english i am a spanish speaking people

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I recommend you to use Unitronics approved USB-to-Serial converters. You can find converters by contacting your local distributor in your country.

MJ20-PRG is isolated, and require external power, which is obtained from USB-to-Serial converter, DSR for example.

Your USB-to-Serial converter will be simplest one, which use only Rx and Tx lines. So it cannot supply power to PRJ adapter.


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