help on micrologix 1400

aaron_01 · Sep 15, 2014

Hello, I was wondering if anyone can help and point me to a rs-485(rs 232 female) diagram of the pinout of a AB micrologix 1400 on ch2. currently im testing/studying application of a modbus rtu master into communication with a inverter drive w/ rj45 (rs485)with a terminal label (EV,sg+,sg-,gnd). thanks in advanced...

John Soltesz · Sep 15, 2014

aaron_01 said:
Hello, I was wondering if anyone can help and point me to a rs-485(rs 232 female) diagram of the pinout of a AB micrologix 1400 on ch2. currently im testing/studying application of a modbus rtu master into communication with a inverter drive w/ rj45 (rs485)with a terminal label (EV,sg+,sg-,gnd). thanks in advanced...

Not sure if Channel 2 can be used as a 485.
Per AB Pub. 1766-um001:

Connecting to Networks via RS-232/RS-485 Interface
The following protocols are supported from the RS-232/485 combo communication
channel (Channel 0) and the RS-232 communication channel (Channel 2):
• DF1 Full Duplex
• DF1 Half-Duplex Master/Slave
• DF1 Radio Modem
• DH-485
• Modbus RTU Master/Slave
• ASCII
• DNP3 Slave

RS-232 Communication Interface
The communications port on Channel 0 of the MicroLogix 1400 controller utilizes a
combined, isolated RS-232/485 interface. RS-232 and RS-485 are Electronics
Industries Association (EIA) standards that specify the electrical and mechanical
characteristics for serial binary communication. They provide a variety of system
configuration possibilities (RS-232 and RS-485 define electrical connection characteristics,
not protocols).

The MicroLogix 1400 controller supports an additional, non-isolated RS-232 interface

on Channel 2. One of the biggest benefits of an RS-232 interface is that it lets you

integrate telephone and radio modems into your control system (using the appropriate
DF1 protocol only, not DH-485 protocol), but it is for point-to-point connections only between two devices.

Kidblue · Sep 15, 2014

Hi,

Pretty sure CH2 is RS232 only on the ML1400 - you will need to to use CH0 (8-pin mini Din) if you want to use native RS485.

Personally i would use a 1763-NC01 to allow easy connection of the RS485 interface.

Regards,

Rob

Ken Roach · Sep 15, 2014

I agree that the 1763-NC01 is an excellent way to connect the Channel 0 port to an RS-485 network.

Even if you are not using A-B drives, the configuration methods used to connect to PowerFlex 4-class drives with the MicroLogix and Modbus RTU may be of help to you.

Here's a nice application note about those methods:

http://ebooksdev.net/file/controlling-powerflex-4-class-drives-on-rs-485-modbus-rtu-.html

aaron_01 · Sep 15, 2014

oh i didnt know that since micrologix 1400 on rslogix ch2 settings can be configured as a modbus rtu thanks for the help...

instead ill use the df1 cable terminal 1 for data b+ and terminal 8 for data a-, terminal 2 for gnd evrything made sense now

help on micrologix 1400

aaron_01

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John Soltesz

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Kidblue

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Ken Roach

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aaron_01

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