read temperature from OEM device from it's RS232 port

I need to read temperature from an OEM device.
OEM device has an RS232 port which is connected to a 1766-NC01 (to micrologix)
(I have no coding anything yet in RSLogix 500, just try to configuration first)
I did a ASCII configuration but seem like I dont see anything:

Echo Character Count =0
Received Character Count =0
Bad Character Count =1

Do I miss something here !?
Thanks

Double check your wiring, and port setting like baud, number of data bits, parity of the temperature device then verify that the MicroLogix port matches everything.

Which model of MicroLogix are you using ?

The 1763-NC01 cable connects the RS-485 pins of a MicroLogix 1100 or 1400 Channel 0 serial port to screw terminals. To use it, you need to set the Handshaking mode of the port to "No Handshaking - 485 Network".

If you want to connect to the RS-232 pins of the Channel 0 port, use an ordinary 1761-CBL-PM02 cable.

What protocol does this OEM device support?

Can you post the make and model of this device? (manual)

I have no coding anything yet in RSLogix 500, just try to configuration first

Click to expand...

Presumably the OEM device is a slave. That means it can't initiate communications. It can only respond to a request from the master (MicroLogix). If you haven't written any code in the MicroLogix, then you haven't asked the slave for any data. It will remain silent until asked.

What serial communications protocol does the OEM device use?

the device is InsiteIG 4000
"The auxiliary port of the Insite IG Model 4000 analyzer supports communication with other devices via the Modbus protocol using both ASCII and RTU transmission modes. The maintenance port of the Model 4000 supports only the ASCII transmission mode."

I connect the NC01 to maintenance port (RS 232 cable head to OEM, another head is cut and pin to NC01), channel 0.
@Steve : So what command I should use ? I'm using ACL to clear the buffer at the first scan, then I use the ACL, that all !

I will re-state: The 1763-NC01 cable gets you access only to the RS-485 pins of the Channel 0 connector.

These will not work if you connect them to an RS-232 port. The two signalling methods are different and require a signal converter, not just a cable.

If you were to use the Auxiliary Port of the InsiteIG device, you could take advantage of the Modbus RTU protocol directly.

Modbus over a serial line has two major variants: Modbus RTU and Modbus ASCII. The RTU variant is the most common and uses nonprintable hex bytes, while the ASCII variant expresses those bytes in printable ASCII characters. RTU is more efficient, and far more common.

The MicroLogix controller only supports Modbus RTU. You could implement Modbus ASCII using custom ladder code, but it would be a significant programming undertaking.

WAIT !

I skimmed the user manual for this device:

http://www.insiteig.com/pdfs/Model-4000-Manual-5-Apr-2005.pdf

On Page 4 it says:

"The maintenance port (J2) is a RS-232 compatible port which can be directly connected to a PC. The auxiliary port (J3) is a TTL-level RS-232 compatilbe port."

In Appendix A, it says

"The maintenance port of the Model 4000 supports only the ASCII transmission mode."

They've given you the worst of both worlds: the port you can physically connect to the PLC doesn't support the protocol used by the PLC, and vice-versa.

If this were my system, I would use a TTL -> RS232 converter and connect to the Auxiliary port.