Hello!
We want to use the MOD-RS485-ISO to use RS485, as we were recommendet by our distributor. Unfortunately the device doesn't work. The signals from the RS485 are not put through to the RS232.
We never worked with OLIMEX-devices before, so what could be the problem?
The voltage is ok on both sides.
An other idea was, that the controller isn't preprogrammed, but I hope that this isn't the problem (we should have be informed about). Or do these products have to be programmed by the user?
We also just want to use the device as a RS232-RS485-Transceiver and not connect it to a development board from Olimex.
Thank you!
I'm having similar problems with the MOD-RS485-ISO. I bought 50 of them unfortunately, and Olimex Support hasn't responded to my queries >:(. I programmed a board with 'PIC-RS485.production.hex', from the MOD-RS485-ISO sub-project from the web. I can't see the board at 0XA0 or 0xFF using PICKit Serial Analyzer, so I'm stuck!! I suspect this board doesn't do true I2C, because if I try program the address into it, the PICKit Serial analyzer responds with "[S_][TX]00[Nr][STER]84[TX]FF[Nr][TX]A0[Nr][P_]", even at 40kHz I2C bit rate. Nowhere in the documentation is the bit-rate mentioned either, so I guess it's left to the poor users to figure out how to make this thing work....
Hey guys,
Try programming the board with the latest firmware, direct link: https://www.olimex.com/Products/Modules/Interface/MOD-RS485-ISO/resources/MOD-RS485_firmware.zip (https://www.olimex.com/Products/Modules/Interface/MOD-RS485-ISO/resources/MOD-RS485_firmware.zip) . The I2C protocol is not "true", it is slightly modified, but still is I2C. To send commands to the board you should send 3 bytes of address, 1 byte for command and 1 for data.
For example if you want to open both TX and RX send the following:
0x48 – 0x04 – 0xA0 – 0x30 – 0x03
Where 0x48 is common address for Olimex I2C devices (This is 7 bit address, so if you want to write the first bit is 0x90),
0x04 – Address for all MOD-RS485-ISO devices,
0xA0 – This is the default address. This can be changed using commands.
0x30 – is the "set clc" command, RX and TX channels
0x03 – means both open.
Because we use modified protocol for our devices, usually the don't show up on different kinds of discovery. The board is tested with 100kHz I2C and should work.
Please let me know how it goes.
Best regards,
Lub/OLIMEX
:) Thanks, that works! In a future revision of the board, is it possible (maybe in firmware now), to RESET the MOD-RS485-ISO? (any spare lines on the UEXT?)
For the other querying party (centra), try this (for RX only):
void CommandSetClcRX(void) {
char ack;
Custom_SWStartI2C();
Custom_SWWriteI2C(0x90); //OLIMEX or, WriteByte(0x90);
Custom_SWWriteI2C(0x04); // //MOD_RS485_ISO
ack = Custom_SWWriteI2C(0xA0); // WriteByte(address);
ack = Custom_SWWriteI2C(0x30); // SetCLC
ack = Custom_SWWriteI2C(0x12); // WriteByte(2);
Custom_SWStopI2C(); // StopI2C();
// return ack;
}
Quote from: centra on February 01, 2013, 03:08:00 PM
Hello!
We want to use the MOD-RS485-ISO to use RS485, as we were recommendet by our distributor. Unfortunately the device doesn't work. The signals from the RS485 are not put through to the RS232.
We never worked with OLIMEX-devices before, so what could be the problem?
The voltage is ok on both sides.
An other idea was, that the controller isn't preprogrammed, but I hope that this isn't the problem (we should have be informed about). Or do these products have to be programmed by the user?
We also just want to use the device as a RS232-RS485-Transceiver and not connect it to a development board from Olimex.
Thank you!
Quote from: VernonB on February 04, 2013, 12:23:28 PM
I'm having similar problems with the MOD-RS485-ISO. I bought 50 of them unfortunately, ...
Hello @ all,
I'm absolutely new here and an absolute beginner with Olimex UEXT interface boards, too. :-)
I also just want to use the MOD-RS485-ISO as a simple converter between UART (RX and TX connection to a FTDI 4-channel chip) and galvanic isolated RS-422 devices.
This should be an easy task but unfortunately there's nothing to see. :-(
Do I understand it right that I still have to program the MOD-RS485-ISO anyway before I can use it?
If so, how should I do this?
Any recommendations are very welcome! :-)
Thanks a lot in advance & best regards,
HFP
Hey HFP,
Generally the OLIMEX devices are two types - host boards and extension boards. Extension boards have the MOD- prefix in their names. Extension boards are expected to be connected to the host boards. So with the host board you can send the commands explained in the manual via I2C (located on UEXT connector pins 5-6). More about UEXT: http://en.wikipedia.org/wiki/UEXT (http://en.wikipedia.org/wiki/UEXT).
You don't have to program MOD-RS485-ISO if you are using common functions. Depending on the purchase date and/or distributor you might have the previous version of the firmware (boards sold/shipped before December 2012) and if that is the case you should refer to the documents in the previous versions of the demo code. The firmwares are located in the SOFTWARE section at this web-page: https://www.olimex.com/Products/Modules/Interface/MOD-RS485-ISO/ (https://www.olimex.com/Products/Modules/Interface/MOD-RS485-ISO/).
Now if you are going for something special - aiming at timings, extra routines etc. you would probably need to edit for the firmware. The firmware is located on a PIC16F1503 microcontroller and MOD-RS485-ISO has ICSP 0.1'-step connector. This means if you wish to change the firmware you will need a PIC16F1503 compatible debugger - for example PIC-KIT3 (https://www.olimex.com/Products/PIC/Programmers/PIC-KIT3/ (https://www.olimex.com/Products/PIC/Programmers/PIC-KIT3/)).
Best regards,
Lub/OLIMEX
Dear Lub,
Thanks a lot!
So now it's already much better for me to understand the basic conditions. :-)
I've never used Olimex host boards before, and I'm also not so much familar with MCU setups, but it seems that there are two possible options for me to get the UART interface connected:
1) enabling UART on every startup (done over I2C)
2) modifying the firmware to have UART enabled by default
Is this correct?
If so, it seems that I have to order the PIC-KIT3 as soon as possible, isn't it?
But the other option could be useful if I'll go for a host board. My target application is a system that should connect a PC application to a number of external sensor devices, maybe just 3-4 NMEA devices or up to 10-15 units. It could be useful to have something like an ARM board between all of these sensor devices, which could collect all external data and deliver it over only one further channel (e.g. USB or Ethernet) to the PC ...
Anyway, my primary task is just to have a reliable (isolated) connection to all of these NMEA (RS-422) devices.
That's why I'd still like to prefer the MOD-RS485-ISO! :-)
Best regards,
HFP
Hey HFP,
Quote1) enabling UART on every startup (done over I2C)
2) modifying the firmware to have UART enabled by default
Is this correct?
Yes. This is correct.
QuoteIf so, it seems that I have to order the PIC-KIT3 as soon as possible, isn't it?
It seems likely, at least because we haven't tested the RS-422 communication (only RS-485). Remember the connector is 0.1' step.
About using a host board option:
It depends on the specific task but generally the I2C line while not very fast is capable of providing interface for many devices connected in parallel. What I mean is that on a single host board with UEXT you might have a number of MOD-RS485-ISO boards (each having your sensors).
A number of reliable ARM boards might be found in our ARM section. But I recommend you to take a look at the following boards:
https://www.olimex.com/Products/Duino/STM32/OLIMEXINO-STM32/ (https://www.olimex.com/Products/Duino/STM32/OLIMEXINO-STM32/)
https://www.olimex.com/Products/ARM/ST/STM32-E407/ (https://www.olimex.com/Products/ARM/ST/STM32-E407/)
https://www.olimex.com/Products/ARM/ST/STM32-P107/ (https://www.olimex.com/Products/ARM/ST/STM32-P107/)
The A13 boards are also a good option for I2C communication - there are I2C drivers ready and working. You need to have a decent level of Linux experience before jumping there though: https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino/ (https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino/) , https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino-MICRO/ (https://www.olimex.com/Products/OLinuXino/A13/A13-OLinuXino-MICRO/).
Again, it all depends on the project. I don't recommend you buying anything before you are 100% sure you need it.
Best regards,
Lub/OLIMEX
Hi, i am trying to use RS485 TTL (no MODBUS) module to let two OLIMEX iso poe communicate with each other.
Somehow the RX and TX port is not recognized and I can not send a "ping" from TX to RX.
UEXT pins:
port 36 -> rx
port 4-> tx
or
no UEXT pins:
port 33 -> rx
port 32-> tx
While connecting the pins to each other over RS485 TTL module I used following code. Could you check to find out what is wrong in my code?
Thanks
TX code:
//#define TX1 4
//#define RX1 36
#include <Wire.h>
#include <MPU6050.h>
#include <ETH.h>
#include <SPI.h>
//#include <EthernetUdp.h> //Load the Udp Library
#include "Arduino.h"
//#define TX2 33 // ext2 pin 5
//#define RX2 35 // ext2 pin 3
int Enable_pin = 3; // gpio -4 bei esp32 nodemcu adc
void setup()
{
Serial.begin(115200);
//Serial.begin(115200,SERIAL_8N1, 32, 33);
//Serial.begin(115200,SERIAL_8N1, 35,33);
pinMode(Enable_pin, OUTPUT);
delay(10);
digitalWrite(Enable_pin, HIGH);
}
void loop()
{
Serial.print("ping"); //Serial Write ADC_Value to RS-485 Bus
delay(100);
//Serial.print("ping\n"); //Serial Write ADC_Value to RS-485 Bus
//delay(100);
}
RX code:
//#define TX1 4
//#define RX1 36
//#define TX1 4
//#define RX1 36
#include <Wire.h>
#include <MPU6050.h>
#include <ETH.h>
#include <SPI.h>
//#include <EthernetUdp.h> //Load the Udp Library
#include "Arduino.h"
//#define TX2 33 // ext2 pin 5
//#define RX2 35 // ext2 pin 3
int Enable_pin =3; // gpio -4 bei esp32 nodemcu adc
int led_pin = 15;
int i = 0;
const int frequency = 5000;
const int led_channel = 0;
const int resolution = 8;
char buffer[1000];
char buffer2;
byte state = 0;
void setup() {
Serial.begin(115200);
//Serial.begin(115200,SERIAL_8N1, 32, 33);
//Serial.begin(115200,SERIAL_8N1, 35,33);
pinMode(led_pin, OUTPUT);
pinMode(Enable_pin, OUTPUT);
digitalWrite(Enable_pin, LOW); // (LOW to receive value from Master)
delay(100);
}
void loop() {
Serial.print("daten 0:");
buffer2 = Serial.read(); // read data and write it to the buffer
Serial.println(buffer2);
if (Serial.available()) { // if any data came to the port
delay(5); // wait a bit for the entire data packet to be accepted by the port
Serial.print("daten 11:");
buffer[i++] = Serial.read(); // read data and write it to the buffer
Serial.println(buffer);
while (Serial.available()) {
buffer[i++] = Serial.read(); // read data and write it to the buffer
Serial.print("daten 12:");
Serial.println(buffer);
}
}
if (i > 0) { // if there is something in the buffer
buffer[i++] = '\0'; // convert the buffer contents to a string by adding a null character
if (strcmp(buffer, "ping") == 0) { // if the accepted string is equal to the ping text
Serial.print("####daten 3:");
Serial.println(buffer);
state = !state;
i = 0; // reset the buffer index
}
}
}
Which Olimex-made boards do you use? How are they named exactly?
Hi, i have the OLIMEX ISO POE IND board.
the RS485 module you can find here: https://www.reichelt.de/entwicklerboards-ttl-zu-rs485-max485-debo-rs485-ttl-p282703.html?PROVID=2788&gclid=CjwKCAjwsKqoBhBPEiwALrrqiHAHa4wjIVtrwUtwieIjQeoPMfMrwECj9z3_mKiWiNVDNdfG1uzE6BoCfxMQAvD_BwE
do you have some advice for me? to proceed with the RS485 example?
thanks
Quote from: harry85 on September 20, 2023, 02:42:26 PMHi, i have the OLIMEX ISO POE IND board.
the RS485 module you can find here: https://www.reichelt.de/entwicklerboards-ttl-zu-rs485-max485-debo-rs485-ttl-p282703.html?PROVID=2788&gclid=CjwKCAjwsKqoBhBPEiwALrrqiHAHa4wjIVtrwUtwieIjQeoPMfMrwECj9z3_mKiWiNVDNdfG1uzE6BoCfxMQAvD_BwE
Hello, harry85!
We do have a similar module (https://www.olimex.com/Products/Modules/Interface/MOD-RS485-ISO) to the one you linked for which we have a library with examples:
https://github.com/OLIMEX/MOD-RS485-ISO/tree/master
You can check specifically the examples Receiver (https://github.com/OLIMEX/MOD-RS485-ISO/blob/master/examples/Receiver/Receiver.ino) and Sender (https://github.com/OLIMEX/MOD-RS485-ISO/blob/master/examples/Sender/Sender.ino).
It has been done for another of our boards ESP32-EVB not ESP32-POE-ISO but the pinout of the UART pins on the UEXT is the same. So that should not be a problem.
Stan, Olimex
Why don't you try something simpler as a start (replace pins with yours) and in one board have SEND defined while in the other RECEIVE defined (comment/uncomment):
#define DE XX
#define _RE YY
#define SEND 1
#define RECEIVE 0
#define MODE SEND
//#define MODE RECEIVE
void Enable (int Mode)
{
digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}
Hi thanks.
but where i need to define the Enable Pin (DE&RE) of RS485 module?
beacsue i need at least three pins TX, RX and Enable Pin.
this is the sender or TX code:
#define DE 4
#define _RE 36
#define SEND 1
#define RECEIVE 0
#define MODE SEND
//#define MODE RECEIVE
void Enable (int Mode)
{
digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
Serial.print("ping");
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}
and receiver or RX code:
#define DE 4 //TX
#define _RE 36 //RX
#define SEND 0
#define RECEIVE 1
//#define MODE SEND
#define MODE RECEIVE
void Enable (int Mode)
{
//digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
//Serial.print("ping");
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}
but somehow is not working ?
i tried this, but still not working. so no output at all:
RX code:
#define DE 4
#define _RE 36
#define SEND 1
#define RECEIVE 0
//#define MODE SEND
#define MODE RECEIVE
void Enable (int Mode)
{
digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
//Serial.print("ping");
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}
Quote from: harry85 on September 20, 2023, 03:44:04 PM...
and receiver or RX code:
#define DE 4 //TX
#define _RE 36 //RX
#define SEND 0
#define RECEIVE 1
//#define MODE SEND
#define MODE RECEIVE
void Enable (int Mode)
{
//digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
...
I noticed that you have changed the values of the macros SEND/RECEIVE as well as changing the MODE (commenting SEND and uncommenting the RECEIVE). By doing so the two programs are basically the same since SEND and RECEIVE are supposed to be constants used later in the "Enable" function.
Try
ONLY commenting the MODE macro. In other words:
Sender:
#define DE 4
#define _RE 36
#define SEND 1
#define RECEIVE 0
#define MODE SEND
//#define MODE RECEIVE
void Enable (int Mode)
{
digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
Serial.print("ping");
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}And receiver:
#define DE 4 //TX
#define _RE 36 //RX
#define SEND 1
#define RECEIVE 0
//#define MODE SEND
#define MODE RECEIVE
void Enable (int Mode)
{
//digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
Serial.begin (9600);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
//Serial.print("ping");
while (Serial.available() > 0)
Serial.print((char)Serial.read());
}
Hi this example still not working, with your proposal.
i try to do this example with two olimex iso poe instead of a nodeMCU.
the example you can find here -> : https://microcontrollerslab.com/rs485-serial-communication-esp32-esp8266-tutorial/
i tried this example with a nodeMCU and it could work. Now i tried to set it up with an olimex poe iso, and it did not work at all.
i assume that the addition TTL RS485 module in between need to know where the TX and RX and Enable_Pin is exactly?
could you please help me with this example provided in the url? :)
Thanks
First of all - I want to apologize for a mistake I made and I mislead you!
The pins DE and _RE are not meant to be the UART TX/RX pins (4/36) as I initially got confused but the pins that goes to the respective signals on the RS485. In my case (I tested it with MOD-RS485 which has a UEXT) the pins were DE=14 (UEXT.9), _RE=5 (UEXT.10). In your case these could (and most likely will) be different and you have to check which are the pins connected to the DE and RE on your module.
And the other thing is since on ESP32-POE-ISO the UART0 that goes to the USB is not the same as the one that goes to the UEXT a different "Serial" is needed. In case you are using the UART1 on the UEXT (TX=4 and RX=36) then you have to use Serial1 for the communication between the modules.
So with these 2 things in consideration try with the following code (of course with edited DE, _RE numbers and the respective value SEND/RECEIVE for the MODE macro):
#define DE 14
#define _RE 5
#define SEND 1
#define RECEIVE 0
//#define MODE SEND
#define MODE RECEIVE
#define USB_Serial Serial
#define UEXT_Serial Serial1
void Enable (int Mode)
{
digitalWrite (DE, Mode);
digitalWrite (_RE, Mode);
}
void setup()
{
USB_Serial.begin (115200);
UEXT_Serial.begin (115200);
pinMode (DE, OUTPUT);
pinMode (_RE, OUTPUT);
Enable (MODE);
}
void loop ()
{
#if (MODE==SEND)
while (USB_Serial.available() > 0)
UEXT_Serial.print((char)USB_Serial.read());
#elif (MODE==RECEIVE)
while (UEXT_Serial.available() > 0)
USB_Serial.print((char)UEXT_Serial.read());
#endif
}
With this code programmed on 2 ESP32-POE-ISO boards (one as sender mode and the other as receiver) and connected properly the boards this should create a one direction communication. Meaning that if you open 2 terminals and input a character on the sender one you will receive that character on the receiver terminal.
I hope this helps you!
The example is also available here now:
https://github.com/OLIMEX/ESP32-POE/tree/master/SOFTWARE/ARDUINO/ESP32-POE_MOD-RS485
wow. Thanks allot, it worked out :)
how can i adjust following part at the receiver to receive the serial message and get some output like:
Received message: 123
Received message: 567
...
the part which should be adjusted:
void loop ()
{
#if (MODE==SEND)
while (USB_Serial.available() > 0)
UEXT_Serial.print((char)USB_Serial.read());
#elif (MODE==RECEIVE) // receiver gets the message
while (UEXT_Serial.available() > 0)
USB_Serial.print((char)UEXT_Serial.read());
#endif
}
thanks in advance.
I am happy to see that it worked! Like I said I got confused earlier and gave you wrong advice the first time.
Anyway on your question now... I am not 100% if I understand what exactly your goal is. My understanding is that you want to see the messages not character by character (as it is with the example I showed you) but instead a whole message (probably a line or something like that).
If it's not that please can you clarify what specifically you mean. But if it is then what you could do something like this:
On the receiver side not to print the character as they are received but instead keep them in a buffer (array long enough to store the maximum length of a message). And when a newline ('\r' or '\n') character is received then you close that array with a 0 (to be null terminated string) and then print the whole string at once.
Should look something like this:
#define STRING_MAX_LENGTH 100
char Buffer[STRING_MAX_LENGTH], BuffIndex=0; // global variables
.....
#elif (MODE==RECEIVE)
while (UEXT_Serial.available() > 0)
{
c = UEXT_Serial.read();
if ((c=='\r') || (c=='\n'))
{
Buffer[BuffIndex] = 0;
USB_Serial.printf ("Received message: %s\n\r", Buffer);
BuffIndex=0;
}
else
{
Buffer[BuffIndex] = c;
BuffIndex++;
}
}
#endif
And depending on the settings of your terminal program whether it sends only carriage return, only line feed or both you may have to adjust the if condition. But generally speaking I think that should do the work (if I get your idea correctly).
Perfect, thanks allot :)
this is exactly what i needed