Micrologix 1400, PF40 VFD, C600 Panelview

Hello,
I am new to plc's as i just graduated from college. I know how to do basic ladder logic but my current job had something come up that needs to be updated. I am updating a brake disc conditioning unit that made a brake disc in one of the motors in the Canadarm. This old unit is running a Servo motor and a some type of dc drive being controlled by a computer running dos.

I chose to recreate it by using a Micrologix 1400 (1766-L32BWA), a Powerflex 40 1hp drive, a C600 Panelview, and a 1hp 3 phase motor.

Now, in college the plcs were always set up for us and we just went in and programmed them to do sequential steps, but now i have to wire them and no where on the internet can i find a wiring diagram of a 1400 controlling a VFD through outputs of the plc to inputs of the VFD.

My questions are:
1. do the inputs of the PLC need their own power or do i just wire IN0 to my switch to COM0

2. same as outputs,just say i want to stop the VFD, do i wire OUT0 to terminal 1 of VFD(Stop terminal) and then DC0 to terminal 4(SRC Common) of the VFD? and tie all of my DC''s (DC1, DC2, DC3) to terminal 4 of the VFD for source common?

3. I want to set up inputs on my HMI, I know how to get into the HMI through internet browser but when i hook up my HMI through ethernet to the PLC, will the PLC just recognize all of the inputs i have made through the HMI?

I know these questions sound pretty basic but i am new and feeling kind of overwhelmed.

Thanks in advance for the help,

Mike Medcalf

I suggest that you look up the manuals for the various components you are going to use. that's the best starting point. that's how i learned it.

then develop your wiring diagram from that information.

regards,
james

Thank you for the response, I have looked up in manuals, I just need reassurance that what i am doing is right, I don't want to mess anything up.

Hi Mike,

What you're doing isn't wrong...you just need some pointers to guide you initially! The particular ML1400 unit you have does have it's own on-board 24VDC power supply for driving your inputs (200mA max from memory). See the picture attached. If you use the +24V COM to supply one side of your input device(s) (Switch/Push button etc.) and then connect the other side to IN0 as the first input (this would be addressed as I:0/0 in the code). Then link COM 0 to the -24VDC COM of the base unit. If you plan to use all inputs on the base, you will need to link COM1/2/3 to -24VDC as well. All would use the +24VDC as their common. Make sense?! I can PDF up a simple CAD sketch if it helps?

You can use the outputs directly if you wish. They are all relay contacts on that particular unit, and you just need to check the grouping arrangement (eg - the first 4 o/ps are all single contacts, but o/ps 4+5 share DC4/VAC as it's common (so what ever supply you connect to the VAC terminal will get switched to both OUT4 + OUT5 when programmed).
Not sure of your application, but a lot of people prefer to use some form of interposing relay on the outputs to give some form of isolation between field device and PLC. This is at your discretion.

Once you have the hardware attached correctly, you can then create your PLC ladder code and HMI interface. You can directly address the I/O you have used or use internal memory bits to control your drive via HMI 'buttons' etc.

Just as an aside, with the addition of a 1763-NC01 and suitable connections, you should be able to hook up the VFD to the PLC via MODBUS (you can set CH0 of the ML1400 as a Modbus Master and it will READ/WRITE to the drive). Could be useful if you wanted to display various drive parameters and performance (Amps/Volts/Hz etc.)

Anyway, hopefully you have something to kick you off!

Hope this helps.

Rob

Rob's input on the MicroLogix 1400 -> PowerFlex 40 I/O connection is very good, and I'd like to add to it.

The PowerFlex 40 drive's discrete Inputs are called "contact closure" type; the drive has an onboard +24V source that you run through "dry contacts" like pushbuttons and relay contacts. Since the MicroLogix 1400 model you chose has relay contacts, you can happily hook them to to the PowerFlex 40.

While the PowerFlex has "sink/source" selection for the I/O, I prefer to just use "Sink" mode and connect +24V to the Input point for Input = True.

As Rob mentioned, the relay contacts on a MicroLogix 1400 are "grouped" to a common terminal. These common terminals have a terribly confusing label "DC5 VAC" means "Relay Output Commont Terminal 5, AC or DC voltage". That's what you connect to Terminal 11 (+24 VDC on the PF40).

I would use Output Group 5 if you will only being doing Start and Stop (Out6 and Out7). If you want to do Start, Stop, Direction, and Reset (and other Digital Inputs) you can use Group 6 (Out 8,9,10,11)

Now, the Inputs on the PLC are different. You use either the onboard +24V power supply or an external +24V power supply to provide voltage for the Inputs. I don't like to use the onboard +24V supply unless I have a very small number of pushbutton type inputs.

I think you should take a step back and consider what that DC servodrive was doing. In general, DC servos have far superior low-speed torque, superior speed control, and sometimes the ability to do position control or torque control.

An AC drive is cheaper and lower maintenance (no brushes !) but the low-end general purpose drives like the PowerFlex 40 cannot hold a candle to the capabilities of a servo controller.

You described the system as a brake disc conditioning unit. Does the motor just turn a spindle ? Is there a torque control or precise speed control requirement ?

Thank you to everyone for replying,
Ken:
The motor is spinning a rotary feed through that is connected to a gear that is connected to 4 more gears, in total spinning 5 fixture conditioning 5 brake discs, I bought a motor capable of doing extremely low speeds, the motor has to go down to 5 rpm and hold for 1 min, then 1 min for 25 rpm, 50rpm, 75 rpm, and then 100rpm for 5 minutes, then all of this in reverse, on the VFD i am using Start/stop/dir/4 dig inputs to control binary pattern to set preset freq's. All of this is in a vacuum chamber at 10^-3 torr to put a certain pressure on the fixtures inside while the motor spins the fixtures and conditions the brake pads.

The speed does not have to be accurate and that is why i went with what i did instead of staying dc and using servo.

The only inputs i have other than HMI: E-Stop, Selector Switch, Door Switch, Vacuum Guage relay output.

Neat !

Is the motor itself in the vacuum chamber ? If so, how do you cool it ?

It sounds like you have the I/O well in hand. The PanelView Component isn't my favorite rapid-development platform, but it's easy enough to configure indicators and pushbuttons with the corresponding data table addresses from the MicroLogix.

yeah it shouldnt be too much longer until it is all together, The motor is mounted on the outside of the chamber and coupled with a rotary feed through that is coupled with a gear, the damn couplers have a 8 week lead time so i cant test properly for awhile.

I am only 20 years old out of college and other than easy ladder logic in college the only other thing i have programmed is an OMRON Zen V2 programmable relay that automated a motor run in procedure to condition the motor windings using some holding timers, I/O, and some Resets.

Side Note:
I bought a vacuum gauge that has analog out and relay out, if i wanted to put that ana out to my analog input of plc, can i scale it and show it on the HMI screen? I am just unsure of how to use a button i set up on the hmi through the plc and to show indicators this way, like do they all have memory locations and i call the status of that location?