Author Topic: serial remote display  (Read 3938 times)

seph

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serial remote display
« on: March 21, 2014, 11:41:49 pm »
I am new in this forum,i need yours valuable assistance from all. i need remote serial display for my digital counter and load-cell meter which work through rs485.
1) Counter bit stream -       1start bit,7data,1stop,even parity,serial asynchronous,open ASCII,master slave up to 99
2)loadcell meter bit strem -  7data,1parity,odd parity,1stop  (7 bit ASCII code is used).
i buy RD4N remote meter which work with rs232&485 selectable but this not work with above displays
RD4N details-bit strem selectable
(1)  7O1-7bit,odd,1stop. (2) 7E1-7bit,even,1stop. (3) 8N1-8bit,no parity,1stop.
so how i select a new remote display? which bit stream need for rs485(two wire) communication? i think some can help me.

EagleWolf

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Re: serial remote display
« Reply #1 on: March 22, 2014, 12:56:53 pm »
I am unaware of this device, but would be glad to help if I can  :)
When you say "Remote Display" do you mean have your computer read the device?

I am not sure if there are multiple devices, but from your description this is how I read it.
You will need to write code (or find a tool capable of this) and I am just assuming ComPort #'s
Parity could be a problem because different languages use different verbage. such as Labview uses
0    None
1    Odd
2    Even
3    Mark
4    Space

PowerBasic uses:
PARITYTYPE
 0 = None, 1 = Odd, 2 = Even, 3 = Mark, 4 = Space. PARITY must be enabled. Default = 0.

Since the numbers happen to be the same, maybe they are some known constant? (I will not bet on it though)
 
Com1:
Baud: Unknown (Assume 9600)
Data Bits: 7
Stop Bits: 1
Parity: Even  (2 maybe?)

Com2:
Baud: Unknown (Assume 9600)
Data Bits: 7
Stop Bits: 1
Parity: 1 (Odd maybe?)

Com3:
Baud: Unknown (Assume 9600)
Data Bits: 8
Stop Bits: 1
Parity: 0 (None maybe?)

Forgive me if I am wrong, but thats the way I read it.



seph

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Re: serial remote display
« Reply #2 on: March 23, 2014, 01:16:35 am »
Hi eagle wolf,thanks

I am not test with computer because Hengstler(count) or DPM(loadcell) micro controller not provide anything about this.Baud rate and address can select through front panel.
i am using multiple devices that is one master with one remote display(slave) total 4 devices ( 4 master and 4 slave), i want to show the values 15 meters away from the machine so using remote display
remote display means - local micro controller[measure or count] device(master) and remote display(slave).
i select rs485 because if two wire use very easy to work, before i was used BCD output micro controller that one need so many wires for remote display

Thanks and regards
seph

Jan Axelson

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Re: serial remote display
« Reply #3 on: March 23, 2014, 12:31:01 pm »
To use multiple devices in an RS-485 network, you will need to define a protocol for determining who can transmit when. This typically requires some way of assigning an address to each display. Then the "master" can send an address and a command to request data from a display. If these are off-the-shelf displays that don't support an addressing protocol, your job will be harder.

seph

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Re: serial remote display
« Reply #4 on: March 24, 2014, 05:37:24 am »
Hi Jan Thanks for supporting me,
If  Master device rs485 output type- serial asychronous,open ASCII,9600bd,1 start,7 data, 1 stop,even parity. and Slave device rs485 input type- serial asychronous,open ASCII,9600bd,1 start,7 data, 1 stop,even parity. these will properly work or not

Jan Axelson

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Re: serial remote display
« Reply #5 on: March 24, 2014, 09:26:24 am »
Yes, as with any asynchronous serial communications, the parameters must match.