GX Developer - Timer Question

Hi there

I am currently translating a Mitsubishi program for upgrade to RSLogix5000. Could anyone please explain to me how the code in the attachment works?

I understand that this is a simple 'greater than' instruction and if T200 is > D130 this portion of the rung will become true. Where I am struggling is with T200, I cannot find a reference to this Timer anywhere else in the ladder software.

The Timer is assigned as a high speed timer in the PLC Parameters but I cannot find a reference in the software which would activate the timer nor set a preset value.

Am I missing something very basic here?

Many thanks
Woodward_UK

have you used cross reference function for search?
if yes and there is no coil T200 then its probably some legacy rung


from what i know GX will compile "T" contacts even without respective coils in program

If you can't find T200 anywhere else, then I'd say this is a case of a code scrap left behind after a program change. What model of PLC is it?

T200 is a 10mS timer, if there is not another reference to T200 in the program then the value of T200 will be always zero.

This rung is very likely an unused timeout.

Thanks for taking the time to reply guys. It does look like unused code.