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PLC CPU A1Scpu-S1 Remote I/O master card cards fitted Melsec I/O A1SJ51T64   Various remote I/O cards fitted for example: AJ55TB3-8D   Problem being experienced:   Parity error light flickering on master card On reading the manuals this indicates to bad signals from a remote I/O card or electrical noise problems in the data cable. No other error lights to indicate a particular remote card in question. Spurious signals to the main PLC come from various I/O cards, not any card in particular. The weird bit is if we cool the master card using compressed air the parity light extinguishes and we have no issues.   Things tried so far:   Changed the master card but same issue. Data cable from PLC to remote station (but not the daisy chains between the remote cards) If the daisy chain was at fault We’d expect to see error lights on the Mastercard at the point of daisy chain failure. Checked the voltages of data and incoming supply - both stable and correct. There are 2 mastercards in total on one rack and another on an additional rack. One card has given issues for years but now a second card is doing the same on the same rack.   Other things to possibly try:   Change all the remote I/O cards associated with one Mastercard initially but not sure if we have enough of this old gear in stock to do so. Change the daisy chains Change the main plc backboard. Manual attached. Any help or similar experienced would be greatly appreciated. manual_IB(NA)-66574 (2).pdf

I want to use D00.0 as a switch on a ladder program. I have no issues with this when programming an FX3-U but it wont let me on an FX3-G. Am I missing something obvious?     Thanks in advance for any help.

found it!

I've gone to add a retentive timer (ST) to modify a program on a R64P and it doesn't recognise the device. From what I've read it says I need to set the points for the device in the parameters but I cannot find this setting any where. Can someone help?

Solved it but it looks ugly! See file. Maybe look at it again once everything else is ready. I need to change the "10" values to the actual number of grids. grid counter.pdf

Bit of a begineer here (first post), I have been asked to look at conveyor chain links on a conveyor that carry fixed magnetic grids to hold metal pans. These grids can get damaged and we want to inspect each grid. At the moment I am programming using GXworks to a FX2N and then using a Proface HMI to show data and have some simple counting logic to count up the chain links (3785 of them). So from 1 to 3785 the plan is to count up and show the count on the HMI and go back to 1 after I reach 3875 chain links as the conveyor does one full revolution. However, sometimes after a crash the chain has to be reversed. If it is reveresed at chain link (for example) No.2 the counter goes 2,1,0,-1,-2,-3 , etc etc, when I need the count to read 2,1,3785,3784,3783 etc etc.  How best to tackle this problem? Thanks Graham