ML1400 PF40 Modbus

i have got setup in the shop a 1400 with a 1763-nc01 adpator to allow me to talk MODBUS to the drive. so far i have setup both the drive and 1400 as follows:

MODBUS MASTER (PLC)
9600 (AND ALSO TRIED 19200)
NONE
1
8
drive set as node 1

for the wiring i am using 1 twisted pair and a drain wire, i have read that you need 2 pairs and use one of the pairs as a common but i have also seen and read just using 1 pair, which is how it shows in the drive manual for the PF40 so anyway i have the setup as the following:

on the NC01 i have A and B connected to the pair and the drain wire connected to ground on the block, on the drive end i have the RJ45 screw plugs for pins 4&5 and connected these up to each wire, the drain i have tried connecting to PE and also in the drive manual it says try connecting this to terminal 4 which is the network common, but to no avail, i have the resistors fitted at both ends and tried various wiring setups as per the manuals, what im really struggling with i believe is to be the correct wiring for the NC01 as i crnt find proper wiring diagram for this.

when i tried send a message:

Ch0, Modbus command 03, N10:0, 1 element, 16 bits

target device:
msg timeout 2
modbus address 8449
node 1

all i get is a fault (HEX)37 message timed out in local processor


any help would be greatly appreciated

Rob

A common configuration issue is the "handshaking" setting for the serial port.

Channel 0 on the MicroLogix 1100 and 1400 has both an RS-232 interface and an RS-485 interface, but both are routed to the same transceiver chip. To activate the RS-485 pins, you need to set the port for "No Handshaking (485 Network)".

This connection uses one data pair (Data A and Data B) and uses the chassis ground as the "Data Common". It is vital that the PowerFlex and the MicroLogix be grounded to the same thing.

Rob,

Definitely check Ken's suggestion. If you still have issues, let me know...we connect the ML1100/1400 regularely to the Powerflex 4 range and have schematics you can check against and code to use as a reference if it helps!

Rob

i have just got home, just checked on my laptop and it is set for no hanshaking but not the no hanshaking (485 network)

ken, on the nc01 it has both comm and grd terminals and on the PF4 it says to common terminal 19 to PE and connect the drain wire to both PE and terminal 4

im not back to work till tommorrow morning so i will check then, rob do you use the NC01 adaptors? the scamatics would be good if you have them to hand and if you dont mind me having a look at the code, i have some already wrote out but as you do these alot you may have a better way of doing it.


cheers

Rob

Rob,

No problem with code...will dig some out!

I've attached a couple of (screenshot) schematics if it helps? (i can send you the proper schemes but would need to 'confidential' them!!)

One thing we have found when wiring the drives up is to NOT connect the '04' terminal to ground as shown in the attached shot. It causes us huge problems with Modbus Comms when the motor is running...!

Hope it helps!

Rob

cheers rob

just to let you know i got it working at last the other week, thankyou ken for pointing me in the right direction, it was setup for no hanshake, but i didnt see the no hanshake (485)

and cheers rob for the drawings i redid the wiring as you advised and ready to install the panel.

cheers

Rob