GXWorks3 GXDeveloper3 Notes

Set Device comment using Navigation Tree View -> Device-> Common Device Comment

Q1. Blinking erratic display of values when choosing Controller Type : FX
A1. Communication issue between the GS2110 HMI and the FX5U PLC over ethernet was resolved by the following settings :
System Tree View -> Controller Setting ->CH1->Controller Type : Melsec iQ-F, I/F : Ethernet Multi
Unit type : FX5CPU, IP Address : 192.168.1.17, Port : 5562, Communication TCP

Q2. When communication between the FX5U PLC and the GS2110 HMI was established the GXWorks3 Programming software was unable to go online with the PLC - gives communication error
A2. The PLC connection set to "Direct" and not "Via Hub"

Q3 Unable to establish simultaneous communication to FX5U PLC with SCADA (MX OPC Server ) and HMI ( GS2110 )

Need to add Melsoft  device to correspond to the HMI as shown below

Q4. Functions and Function Blocks

Functions : 

1. Do not get instance numbers when used in the Program

2. Instance values are not saved between consecutive calls

3. You cannot debug into a Function Block and do not get to see the current values

Function Blocks : 

1. Have instance numbers when used in the Program

2. Instance values are saved between consecutive calls

3. You can debug into a Function Block and get to see the current values

Q5. Float Inputs ( eg D200 and D201 ) to the function block is considered as Integer ( only D200 ) and this is subjected to implicit Integer to Float conversion using only D200 and not D201

A5. Use D200(D201) -> DEMOV -> FCB/FB Input

Q6. Double Word Signed Outputs from the function block give conversion error when assigned to  say D300 

A6. Use FCB/FB Output -> DMOV -> D300(D301)

Q7. Which "Local" registers can be used to store the results of DEZCP instruction in a FCB/FB ?

A7. Define Local Variable as Bit Array eg myarray Bit(0..2)

       At the output of the DEZCP instruction use only myarray not any bit

       The results are stored in :

       myarray(0) ( less than zone ), myarray(1) ( in zone ),  myarray(0) ( greater than zone )

Q8. 5V to 24V Level Shifter using LM339 Comparator IC

A8. In the case of a comparator, if its output is open collector, then it requires a pullup, and it would invert the logic; so the trick here (to NOT invert the logic) is connecting the 3.3v signal to the inverting input, and the voltage reference (1.7V) to the non-inverting input.

Just to be complete and aware of the implications, the circuit would draw about 10mA continuously while the output is LOW (which is most of the time).

Q9 : I get some error in FX5U PLC - illegal operand shown when clicking on the "Error Status" icons in GXWorks3.
A9. Started by cutting out all the new rungs I had added and pasted them in a dummy project. I then added back the rungs a few at a time. Till I came across the rung with the error. - ZRST function was causing the error when used with two sucessive bits of a word. Replaced with RST function for the individual bits