Running Operation Data Profiles over RS-485

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Running Operation Data Profiles over RS-485

Post by om_tech_support_CF » Thu Aug 26, 2021 12:03 pm

Q: I recently purchased your AZD-KD driver and am looking to run several motion profiles over RS-485. What different methods does the driver offer?

A: If programming over RS-485 (Modbus-RTU) the AZ series Built-in controller driver offers several features to run different motion profiles or operation datas.

Method 1: Binary Inputs (M0-M7)
First we will utilize the remote I/O registers (007Dh). In the image below you can see the inputs assigned from the factory. The M0 - M2 inputs are binary inputs, that when turned on in addition with the start input will run the corresponding operation data. We offer M0-M7 on our AZ series which can run up to 256 operations. All binary inputs can be assigned to the 007Dh register, but must take the place of a factory input.

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As you can see in the above image, when the corresponding binary inputs are activated, the operation data number will be selected. Once the binary inputs are on, the start input must be turned on to run the operation.

If the start input is turned on by itself, Operation data 0 will run.

Method 2: Direct selection (D-SEL0 to D-SEL7)
Next we will discuss the Direct selection method (D-SEL0 to D-SEL7).These inputs are used to run the operation data number that is entered in the corresponding parameter setting. As you can see from image 1, D-SEL0 to D-SEL2 are assigned from the factory. The same as the binary inputs, all 8 direct select inputs can be assigned to the 007Dh register. The initial values for each input are listed in the image below. However, any operation number 0-255 can be assigned to a corresponding direct select input. You can also select how this runs with the D-SEL drive start function.
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Method 3: Net selection number & Driver input command
Now we will discuss the Net selection number and Driver input command. This function consists of 3 different methods, highlighted in different colors in the image below. Methods 1 (blue) and 3 (red) function identically. We just offer 2 sets of registers for convenience. Method 2 (green) is similar, but is essentially a 1 shot signal. Meaning once these registers have been turned on, they turn off automatically after 250 µs. So it is not required to write a 0 to the holding registers after sending a query. This method works by writing an operation data number to the NET selection number register. You must then write an 8 to the Driver input command register to run the operation data number previously written.

We get 8 from the remote I/O list. The start input is in Bit3 which is 2^3=8.

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We will now show an example of this final method with the free software, ComtestPRO by Baseblock, which can be found on Google.

I will be running operation data 1 and 2. Looking at the below image from our free software, MEXE02, you can see the programmed operations. Operations can be programmed over RS-485 additionally.

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Registers 0072h, 0073h, 007Ah, and 007Bh (ref screenshot above) set the operation data number to be run. Then you must turn on the start input by writing a value of 8 to 0075h for method 1 or 007Dh for method 3.

I will now write to multiple holding registers and select my desired operation and run it simultaneously.

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In the above image you can see I am writing to 4 holding registers, starting at register 0072h. I am writing:
0 to 0072h
1 to 0073h
0 to 0074h
8 to 0075h
This will run to a position of absolute zero. If I changed the 1 that I wrote to 0073h to a value of 2, the motor would go to a position of 25mm. (See screenshot of MEX)

Now since the start input has been turned on, we must now write a 0 to turn it off.

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Registers 007Ah to 007Dh function exactly the same, as stated earlier.

The only difference between registers 0076h to 0079h from the previous section discussed, is that 0076h to 0079h are a 1 shot signal (automatic off). So you do not have to write a 0 to turn off the start input and can send commands back to back.

Should you have any further questions please contact us at [email protected] or call at 1-800-GO VEXTA.

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