The GS20 family of variable frequency drives have tons of features, but one of my favorites
is they can use a keypad from the GS4 family of variable frequency drives.
Why is that such a big deal?
Let’s do a side by side comparison and you will see.
To do that, let’s use the GS20 drive’s keypad when we are locally working on the
drive and we’ll use the GS4 keypad as a remote keypad.
So let’s set the local frequency to be controlled by the GS20 keypad potentiometer and the local
run/stop to be controlled by the GS20 keypad buttons.
The GS4 keypad is a Modbus RTU Master, so we need to set the drive’s remote frequency
to be controlled by RS485 and the remote run/stop to be controlled by RS485.
The GS4 keypad is at address 1, uses 19.2 K baud and this protocol, so we need to set
the drive to accept that.
These are the motor parameters and ramps I used for my motor in this demo.
Now I just plug any standard ethernet patch cord into the RS485 port on the GS20 and into
the back of the GS4 keypad.
That provides the communications and the power to the keypad.
I’m going to reset this GS20 drive to factory default so you know exactly where I am starting
from.
We haven’t set up the communications parameters yet, so the keypad gives us an error.
Let’s fix that.
I’ll go to parameter 9.00 and verify it’s using address 1 – yep.
Go to parameter 9.01 and change that to match the GS4 keypad’s 19.2 K baud.
And go to parameter 9.04 and change to the correct protocol by entering a 13.
Now if I reset the keypad, there it is!
We can now change parameters from either the GS20 or the GS4 keypad.
Let’s use the GS4 keypad so we can see how it works.
I’ll hit MENU and select the parameters menu.
I can use the up/down arrow keys to move the cursor to the menu I want.
The first thing you notice, is you see both the group number AND the group description.
If you see a little arrow here that means you can scroll to the right to see more.
This is what I would see on the GS20 keypad.
To configure the motor, I just scroll to the motors group – I don’t have to look up
which one that is in the user manual!
Press ENTER and I can now scroll through the motor parameters.
This is the motor's rated amps, so I’ll hit enter and change that to match my motor.
Press enter to accept and we see the END confirming it.
It’s so cool that everything I need to know about this parameter is right here.
The parameter number, the units, the value, and a description.
Which means I don’t have to look that stuff up in the manual!
Press escape to go back up a level.
Here’s the motor's rated power.
I need to change that to match my motor.
Notice that I can either scroll through he values or select a digit and change it.
And again, everything I need to know about this parameter is right in front of me.
And I’ll go ahead and change the motor's rated speed while I’m here.
I’ll press escape twice to get back up to the groups menu and then select the system
parameters where we can change the local and remote configurations.
Parameter 30 is the local – or some people call it the hand configuration for the frequency
source, so let’s change that to the variable resistor – or potentiometer on the GS20
keypad.
Again, I don’t have to look that up, I just scroll until I see what I want!
There it is!
And press enter to accept that.
I’ll hit escape to back up a level.
We want the local or hand operational source to be the buttons on the digital keypad and
we see that IS the default so I’ll hit escape to get outta here.
The REMOTE frequency source is in parameter 20.
It’s currently the GS20 digital keypad.
I’ll scroll until I find the RS485 and there it is!
Enter to accept, and esc to back out a level.
The remote source of operation – run/stop - is the GS20 keypad, so let’s scroll that
to RS485.
There it is.
Hit enter to accept.
ESC to back up a level.
How cool is it that I didn’t have to look any of that up? I just scrolled to find
the option I wanted.
Ok, you got the idea.
I went ahead and did the ramps to finish this out, and pressed escape until I got back to
the top level. The second big advantage of using the GS4 keypad
is you can see three lines of status at the same time.
Here I can see the frequency setting, the actual frequency going out to the motor, the
user display which is currently showing bus voltage, and if I scroll down, I see the current
draw.
This is circular, so I can just keep scrolling in either direction.
And check this out!
If I scroll to the user display, this tells me I can use the left right arrows to view
all the possible user display options!
The left arrow scrolls forward through the list in the manual.
This setting is independent from the user value defined in parameter 00.04.
If I bring up parameter 00.04 on the GS20 display you can see it doesn’t change when
I scroll through these.
But if I change parameter 00.04 then the GS4 keypad does reflect that change.
Another other advantage of the GS4 keypad is the local remote control is right on the
keypad.
We said we want to control the drive via the GS20 keypad when in local mode.
This tells us we are currently in REMOTE mode, so let’s hit this button to go to local
mode.
Now I can change the frequency and run the motor from the GS20 keypad.
I can’t change the frequency or run and stop the drive from the GS4 keypad.
If I switch to remote mode then I can’t change the frequency or control the motor
from the local GS20 keypad, but I CAN control the motor from the remote GS4 keypad.
And if I scroll to the frequency setting and hit enter I see I can change the frequency
from the remote GS4 keypad either by single digit or by scrolling.
Having quick access to the local and remote configurations without an external switch
is a huge bonus for the GS4 keypad.
The GS4 keypad also has a forward and reverse button so I can quickly change that whenever
I want to without having to add an external switch.
It only changes the direction – you still have to hit the run button to make the motor
spin.
But you can change direction while the motor is running.
The motor ramps down, and then ramps back up in the other direction.
You can JOG the motor from the GS4 keypad by holding the F1 button.
The motor will jog in the direction chosen here and according to the jog parameters you
set up in the drive.
These other function keys don’t do anything on the GS20 drive.
If we hit the menu key we can change the parameters – as we saw earlier - and the quick start
menu is a GS4 drive thing, it doesn’t apply to the GS20 drives so we’ll skip that one.
You can lockout the keypad – now accidental button presses can’t change anything.
To get back, just hold the escape key for 3 seconds.
Now I can change things.
The fault record shows the last 20 faults and if you select one, you see the all the
pertinent data that was captured when the fault occurred, including the amps, voltage
and DC bus values.
You can control the PLC from the GS4 keypad.
You can copy up to four different GS20 drive parameter sets into the key pad, then take
the keypad to another drive to write those parameters back out.
When you select one you give it a name and hit enter.
It’s copying and verifying a LOT of stuff, so be patient.
It’s still a lot faster and more accurate than entering them all by hand yourself.
I’ll fast forward through the rest of this. That’s a super easy way to update a
bunch of drives or to keep a backup of this drive's parameters.
Of course, you will need to set the communications parameters on the new drives to be compatible
with the GS4 keypad before you can do this.
You can copy four sets of the PLC parameters that you can use to configure other drives.
Same process.
You can change the display settings, the time and date, and your language preference.
You can even change the default startup screen to be the GS20 logo or this initializing screen.
Finally, if you hold down the up arrow when you apply power to the drive or simply plug
in the remote keypad, you can see the current firmware version of the GS4 keypad.
Please make sure you have the most recent firmware for your GS4 keypad.
There is a separate video showing how to upgrade the firmware using the free GSOFT2 utility
and you can always download the latest firmware from the AutomationDirect.com website.
In this summary chart you can see the optional GS4 keypad adds a lot of the high-end GS4 drive
features to the GS20 drive family.
And yes, that keypad is available as a stand-alone part number at AutomationDirect.com.
Notice that only the GS20 keypad shows you which pre-defined parameter set you are using
if you set parameter 13.00 to one of the pre-defined application types and of course the non-NEMA
4X GS20 drive's keypad has a potentiometer.
Click here to see all of the GS20 variable frequency drive video tutorials.
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