1769-ascii

Hi there

I am new to ASCII, right now want to send a command, g r0x32, to a ASCII device to get feedback. I think I need to send a string with content of this command out, am I right? I appreciate your help if you have experience with ASCII or this module. Thanks in advance

Are you using it with Compactlogix controller or a Micrologix 1500?

Thanks for reply. Yes, I am using it with 1769-L33ER

You don't have to use String datatypes with the 1769-ASCII.

Instead, you follow the directions in the User Manual, Publication 1769-UM012. [Direct Link to PDF]

There are also examples in the samplecode.rockwellautomation.com database. Use "1769-ASCII" as your search keyword.

The basic steps for outputting a series of bytes from Channel 0 of the 1769-ASCII module are:

1. Put the output data bytes into the Local:S:O.TxData array.
2. Put the number of bytes to transmit into the Local:S:O.TxDataLength tag.
3. Increment the value in the Local:S:O.Ch0TxID tag.

Every time that TxID tag changes, the module will send the number of bytes you specify out of the serial port.

What exactly are the ASCII characters you need to send ?

You posted that you need to send "g r0x32".

0x32 is usually a way to write a hexadecimal value. 0x32 is actually the ASCII value for the number "2".

What you described sounds like four characters: Lowercase g, Space, Lowercase r, and the number 2. Is that correct ?

Thanks so much, Ken.
Yes, I need to send g r0x32 out first then read position feedback v xxxx.
I can put g r0x32 in the value of Local:S:O.TxData array, and the length will be 4, am I right?
Here I am not understand RxID since the port (ch0) is connected only to one device but it can visit more than one destinations such as memory, flash, registers. The command g r0x32 is going to ask the device send feedback of position data stored in memory. Can I keep the RxID unchanged if I only concern position?
I attached data tag/type. Could you please tell me the assignment of value is correct or not. I appreciate your help and time.