Internet PLC Forum

How hard would it be to provide a DLL version of the TL5 Uploader program?  It would be great to give our HMI software the ability to update the PLCs in our machines rather than relying on the customer or field service rep to select the proper COM ports in the Uploader when doing upgrades (we use two T100MD888+ PLCs in our machines).

Just a thought.

I have a feeling I already know the answer to this but I figured I should ask anyway.  Is there any way to recover a program from a PLC in the event you lose the source code?

Has anyone successfully implemented a communications watchdog using ladder logic?  I'm trying to ensure that our PLC isn't able to do anything it shouldn't if our HMI loses communications with it.

What I do now is the following:



The ResetWDog CusF contains:

TIMERPV[1] = 50
TIMERBIT[1] = 0
CLRIO WatchDog

From our HMI we repeatedly set the WatchDog relay using "Force Set/Clear Single I/O Bit" command ("Wbnnnnxx").  This causes the ResetWDog custom function to be called which resets the timer and clears the WatchDog relay.  This timer is constantly counting down thanks to the Norm.On input.  If the timer counts down to "0" the WDExpired custom function gets called which performs the appropriate actions (currently resetting the PLC which puts it in a "frozen" startup state).

This works 95% of the time but once in a while the timer inexplicably expires.  Monitoring my HMI doesn't reveal any obvious communication delays.  The timer is currently set to 5 seconds and the HMI is probably resetting the WatchDog relay 10 times a second.

So maybe I'm going about this all wrong.  Has anyone else tried to achieve a similar goal following a different path?

On our machine we have a couple of different 2-wire switches wired into T100MD888+ PLCs.  One has problems and one works fine.  Here are some specs:

Switch #1: Pressure switch (SMC part # PS1000)
Load voltage: 12-24 VDC (we're running at 24V)
Load current: 5-40 mA
Leakage current: < 1 mA
Internal voltage drop: < 5 V
On voltage measured at PLC input: 3 V
Off voltage measured at PLC input: 15.2 V

Switch #2: Proximity switch (SMC part # D-C73)
Load voltage: 24 VDC
Load current: 5-40 mA
Leakage current: not specified
Internal voltage drop: < 2.4 V
On voltage measured at PLC input: 1.6V
Off voltage measured at PLC input: 19.3V

Switch #1 is the one that doesn't work properly.  If I power up the PLC and the switch is already on (i.e. air pressure is on) the PLC reads the input as on.  If I turn down the pressure until the switch goes off, the input goes off as well (so far so good).  However, if I now increase the air pressure until the switch turns on, the input doesn't turn back on again.  The only way to get the PLC to read the input as on is to power up the PLC while the pressure is on.

I tried the two suggestions mentioned in this thread but neither achieved anything.

I know this really isn't a TriPLC issue but I was hoping you might have some insight into this since you are more familiar with the design of your PLCs.  Plus, you've been very helpful with questions like this in the past.

I realize this probably isn't a TriPLC question specifically but I'm sure many people here use ICP's modules so hopefully someone can provide some advice.

We've been unable to configure our I-7018 modules from the T100 PLC.  I tried putting the following line:

A$ = NETCMD$(3,"%0101OF0600" + CHR$(13) + "~")

in the 1st.Scan circuit but I don't get a response from the module (i.e. A$ is empty).  I know communications are working because I am getting responses in the circuit that reads the inputs.  The module just seems to refuse to respond to the configuration command.

I've tried moving the config command to another circuit that I can trigger manually while monitoring (thinking maybe the 1st.Scan happens to soon after powerup and the ICP module isn't ready yet) but that resulted in nothing as well.  I finally resorted to breaking out my RS485 adapter and configuring it using Hyperterminal but it would be nice if we didn't have to do that in the future.

Any ideas on what I could be doing wrong?  Is anyone else successfully configuring their ICP modules from the TriPLC?

(It did just occur to me that we probably shouldn't be sending the configure command in the 1st.Scan rung anyway since that probably causes the ICP module to write to its EEPROM.)

I was about to make a new thread about a bug in version 5.33 of Trilogi but it seems to be related to one of cdenk's complaints here.

Regarding (1), it seems this is something that was broken in 5.33.  The previous version would always remember the last folder used without requiring you to open the project appearing on the recently opened list.

A minor bug but I thought I'd just point out that it worked fine before.

It happened even with DIP switch #4 turned to ON.

I don't know if this is a helpful clue but the only way to get a response from the PLC after this happens is to close and re-open the connection from the "Serial Communications Setup & Test" dialog.  Sending "IR*" gets no response until I do this.  Maybe this is to be expected though

Our application, which doesn't communicate through TLServer, doesn't seem to be seeing these same errors.  Maybe it's just TLServer that's having a problem.

Could this be related to Java perhaps?  My Java version is 1.5.0_06

Edit 1:

Hmm.  I'm starting to suspect either my Java installation or else my PC itself.  I have a brand new laptop and this is the first significant Trilogi development I've done on it.  I'm using USB serial adapters but I used these on my old machine as well.  My old machine was USB 1.1 and the new one is 2.0 but I wouldn't expect that to matter.

I do have Java 1.4 installed on my machine as well.  Is there a way to force a Java app to use an older set of runtimes?

Edit 2:

Ok, I figured out how to force TLServer to use Java 1.4 and that didn't change anything.

I also tried monitoring a different PLC running a different program (one that doesn't use the RS485 port) and the same problem arose.

So it seems like it must be my PC or its USB ports or something.  Sorry for the false alarm.