modbus via freeport, and ports1 and 0 s7 200

Im junior plc programer and i need Your hellp if you have time to spare.

Im trying to make modbus rtu communication with pc as master and plc 226 and one lift call bord as slave.

im using qModMaster to simulate modbus master.

Problem is i dont know how to connect that lift call bord to this modbus connection, i had successfully connected pc and plc via modbus using rs485 cable on port 1, but modbus comunication wont work on port 0 when i use libery for port 0.

My plc has port0, port1, and freeport. I tried using freeport but i dont know how, eaven with smb30 and 130 are set up, it  wont work. Pinout on lift call bord is 24vpin mod+pin mod-pin and com.

i newbie please hellp if You can

Hello,

maybe one little know how:

1. you need to be sure that lift card???? support same Modbus protocol as PLC use, in this case RTU.

2. if yes, you can use daisy chain connection (extend) serial network from PLC port to that lift board. Check web what is daisy chain connection on RS485 2-wire connection.

3. here is expected same communication parameters like speed, parity, ... same on both devices.

4. next important thing is addressing on bus, each of Slave need have unique address which is used from Master for data collection.

Hope this is good start for you, anyway you can also step inside SIMATIC S7 - Hardware conference and check S7-200 Conference for additional infos. No problem continue here for next ideas, questions.

Lift card has same modbus rtu, its 9600bps,8,N,1

its slave address is set manual to address 4 so no prob there, 

What i wanted is to use freeport as port 1 cous somewhere i saw that this library sets port1 and freeport for modbus communication

Hello,

I start with some infos from your side.

"... I have Port0, Port1 and Freeport..." -> Port0 and Port1 have same functionality but one rule exists that if some communication protocol occupied this port, port is not available for other. Freeport is protocol which you can use over Port0 and Port1 as you need but with also that restriction mentioned. Freeport take simply as free user defined protocol where you simply can define own frames for communication, simply user defined. Generally, you can also implement Modbus with your hands but you need be skilled with that. I expect better unplug that PLC from bus and connect your lift to it with direct connection as is already described. Here in 2 wire is Data+ and Data- needed, maybe also GND. If your lift has address 4, you can use that prepared Modbus library and only change Slave address inside block to 4. Then check inside lift board documentation where are required registers addresses what you need, collect.

Update: eeeehm pls describe again clearly why you need implement Freeport, what Modbus library you're use or what you need to do?

Sry, you can check Help inside Microwin about SMB, there you can find how to init comm port for Freeport to have Modbus functional because that library is created with Freeport protocl logically.

Hello,

just one hint what I remember, initialisation of Port with specific protocol need to be inside first scan of CPU - SM0.1 hope good remember. Procedure is simple, check SMBx (what port you want use for Free[port) help and set values (Bytes, WORDs, ...) as is described there inside that SMBs. This set of values need to be in that first scan sequence to be port initialised correctly.

Well, i use my pc as master, so connecting lift call bord and plc would be connecting two slaves..

Well i still cant get modbus to work on port 0 but it works on port 1, and i have freeport on the side of plc its independed, eatherway making that freeport to work like modbus looks like to commplicated for me for now, and im in hurry whit this proyect so i listened to your advice and hand made daisy chain, connected it to plc pc and lift call btn board, now i can see my slave plc on my pc but when i go on address 4, it says timedout, once it said that wrong slave answered on command. 

i dont know what to do now, 

Thank you for hellp till now 

I connected new plc to the bus and i can see it and old plc on the pc. Still dont see lift bord, ill leave here my program for modbus on plcs its lbr for port 1, when i make same one for port 0 in onother program it wont work, its not connected to hmi or anything, when i program port 0 for  modbus i use port 1 to download program.

ill post all instructions i have for bord and how does it look like