GX Works3 FX5U - Adroit - Memory Device Retention (Latching)
Introduction:
This is a short article explaining how to configure memory Device Retention (aka latching) on a Melsec iQ-F PLC - via GX Works3.
From here - the PLC is being interfaced with Adroit SCADA to demonstrate the device retention concept.
The Process Procedure:
The following applies;
A Battery is required for retention purposes;
The Super-caps are insufficient, not connected
The Device/Label Memory Area Setting
In this example - we will be setting the data register range (D) for retention
Latch Range settings for - latch (1)
Latch Range settings for - latch (2)
The Difference between Latch 1 and Latch 2:
The final product after the latching:
As for the programming itself
- IF the values are manually entered – and retained by the PLC – then the above settings are sufficient. (Static values – like parameter coefficients, constants)
a. Attached sample program demonstrates this.
GX Works3 FX5U - Adroit - Memory Device Retention (Latching).gx3 (632.0 KB)
- IF the values to be retained are as a result of a Function Block output (like counters and timers) – then additional programming is required.
a. Retentive value to be moved to the FB Output value at PLC startup.
b. Attached Sample program demonstrates this
An example:
The following is a demonstration example;
Demonstration Videos:
GX Works3 - setting up - latching of dynamic values (counter values)
GX Works3 - Setting Up - Battery Backed up - Retention Latching
GX Works3 - Demonstration of Counter value retention between Adroit SCADA and PLC
Resource Reference:
The following reference information is applicable:
Proof of Concept Demo
Attached - PLC Program sample:
GX Works3 FX5U - Adroit - Memory Device Retention (Latching).gx3 (632.0 KB)
Attached - Adroit SCADA sample:
GX Works3 FX5U - Adroit - Memory Device Retention (Latching).zip (35.9 KB)