In mk5 tmr is there a list all diagnostic alarms? Where I find?

What does it mean the number 1 in the following alarms:

[tcd1 contact input #32failure]
[tcd1 contact input #31failure]
[tcd1 contact input #29failure]
[tcd1 contact input #20 failure]
[tcd1 contact input #19 failure]
[tcd1 contact input #18 failure]
[tcd1 contact input #17 failure]
[tcd1 contact input #16failure]
[tcd1 contact input #15 failure]
[tcd1 contact input #14 failure]
[tcd1 contact input #11 failure]
[tcd1 contact input #10 failure]
[tcd1 contact input #08 failure]
[tcd1 contact input #07 failure]
[tcd1 contact input #6 failure]
[tcd1 contact input #5 failure]

 

tcd1 refers to the first TCDA in the IONET of a particular processor. In the list of alarms below you did not indicate which processor (<C>, <R>, <S>, or <T>) the alarms are associated with.

Each processor has its IONET that connects associated cards in other "cores" (modules) to the processor. <C>'s IONET connects the TCDA card in Loc. 1 of <CD>; so tcd1 for <C> is the TCDA card in Loc. 1 of <CD>.

<R>'s IONET runs from the TCQC card in Loc. 4 of <R> to the TCEA card in Loc. 1 of <P> to the TCDA in Loc. 1 of <QD1>, and, if so equipped, to the TCDA in Loc. 1 of <QD2>. So, tcd1 for <R> would be the TCDA in Loc. 1 of <QD1>, and, if so equipped, tcd2 would be the TCDA in Loc. 1 of <QD2>. (<QD2> is an optional second discrete I/O core.)

In general when you see a "swarm" of contact input failure Diag. Alarms like this it is indicative of AC noise caused by improper routing of cables during construction--something that is very difficult to resolve. High AC current-carrying conductors run in close proximity to DC conductors quite frequently induces AC on the DC conductors. You can measure it on DC conductors with a true AC RMS voltmeter set to AC, measuring with respect to ground. Usually, AC voltages greater than approximately 40 VAC impressed on DC conductors cause these alarms in Mark V panels.

Examples of poor construction wiring practices include running pressure switch contact input wiring (125 VDC) in the same conduit as 440/480 VAC motor power leads, or running motor power leads in the same cable tray or cable trench as 125 VDC contact input wiring cables.

Also, sometimes when battery charger output filter capacitors begin to fail they can cause excessive AC ripple on the charger output that can cause these alarms.

And, sometimes, the TCDA cards just fail, causing these alarms. The usual cause of failure is long-standing 125 VDC battery ground alarms; frequent lightning strikes in the close vicinity of the turbine/control panel; and poor housekeeping and maintenance practices in the control room where the Mark V panel is located (excessive dust allowed to collect on cards along with high humidity conditions, failed or failing air conditioners, excessively cold temperatures in the room where the Mark V is located in humid locations; water in cable vaults below the Mark V panel; etc.).

You will usually find these alarms, when caused by AC noise, on contact inputs that are wired to contacts that are open. When the contact closes, and shorts, the alarm goes away, but when the contact opens it may come back.

Hope this helps!

 

hi csa

thanks. its no indicate what processes tcda loc1 or tcda loc 2 or tcda loc 3.

 

Well, then you haven't provided the entire alarm text message, including the drop number. Some later GE Mark V HMIs require a secret decoder ring to decipher which processors Diagnostic Alarms are associated with. (Isn't this fun?)

There's one possible way to determine which processor--by looking at the flashing bar LEDs on the TCDA cards. When there are no Diagnostic Alarms on any of the three TCDA card in <QD1> and no Diagnostic Alarms on the TCDA card in <CD>, then all all the bar LED segments will flash in the same sequence and be synchronized (flash at the same rate). When there is a Diagnostic Alarm on any TCDA card, the bar LED segments will flash at the same rate as the others, but not in the same sequency. So, that will tell you.

Unless there are multiple TCDAs with Diagnostic Alarms.

I would hope it would be intuitive that if the TCDA in Loc. 1 of <QD1> was associated with <R>, then the TCDA in Loc. 2 of <QD1> would be associated with <S>, and the TCDA in Loc. 3 of <QD1> would be associated with <T>. I think the Mark V Maintenance Manual has at least a written description of that, if not a diagram/figure showing the IONET(s). (I don't have access to the Mark V manuals at the moment.)