Trouble with MD-HMI

[Maca]

I have a problem with a MD-HMI

The top line of the display is faulty
ie. the first 15 or so of the characters are blank
the last 5 characters  are OK

Hardware:
                  MD-HMI
                  T100MD-1616    r49

If I change the line number it will be displayed correctly on any of the other lines.

[support]

Looks like the LCD display on the MD-HMI has failed. Please contact your dealer for replacement part if under warranty.

[cdenk]

Thanks for the quick response.

A little more info. I ordered a few of the 74HCT14's, should be here Saturday latest.

1: Found on 74HCT595 U05 pin 8 was buckled and bent inward, not very visible until board was out of cabinet. Could have been making contact for some time, don't know. No outputs that area are in use. Fixed, also substituted another chip, no change.

1: When powering up, the LED's remain off for several seconds (it's a lengthly program) until just before the LCD display comes active. Appears to be turned on by software, though only one LED should be on.

2: Added to the very end of the program, a circuit with a 1 second clock contact and a Dfun, CLRIO 2 LEDs, SetIO 1 LED, and Toggleio 2 LEDs. All the LEDs remain on.

3: Wrote a new program with 1 circuit - a 1 second clock and a Dfun that Toggleio all 8 LEDs, and they all FLASHED at one second.  

Thoughts?? Still likely the 74HCT14, or possible some other chip? Chips are cheap could order a few others if a chance.

[support]

74HC595 controls some of the PLC output drivers and 74HCT165 interface to the digital inputs. Damage to these chips may also affect some of chips because of common signal lines such as clock and latch signals. So if you are ordering ICs you may like to order some of these as well. Make sure you get the DIP package when you order  

[cdenk]

1 more item : Outputs 41, 42,43,44 on the EXP are dead. But the PLC seems other wise ok. The LCD including keyboard buttons, and    outputs #27 and lower are OK. Outputs greater than 27, except for41 - 44 are unused and have not been checked.

[support]

Do you mean the TTL/CMOS level output on the EXP4040 or do you mean a standard digital outputs? The standard digital outputs on the EXP4040 are controlled by TPIC6A595NE chips. Each chip control eight digital outputs.

The TTL/CMOS level oututs on the EXP4040 are controlled by the 74HC595 chip next to the header.

The TTL/CMON level inputs on the EXP4040 are controlled by the 74HCT165 chip.

I hope these information helps.

[cdenk]

It's the TTL/CMOS level output on the EXP4040. Is there a common chip to these outputs and the HMI LED's ?

Are schematics for the equipment available? Sure would beat reverse engineering from chip data.

Was going to order the 2 sets of spare PLC's, EXP, & HMI today, has been on list now for a while, but still need this one to work correctly.

[support]

The two 74HC595 next to the TTL/CMOS level output headers are the one that control these 16 outputs.

[cdenk]

It was 74HC595, U04, put a new chip in solved both the Output 41-44 and HMI LED problems. Thanks for the help, still going to order the spares.

[Maca]

 My problem was with my software !

I reused my modified version  of your MD-HMI example program

Thanks for your help.

[cdenk]

Something to be careful with, in particular longer programs. Since Trilogi works from top to bottom, and then sets all the I/O including the HMI at the end. If there is say a SETLCD 1,1, "                    " (should be 20 spaces there) at the end of a function on the last circuit (rung), then no matter what you did higher up on the circuits, the first line will always be blank. (Assuming that last circuit gets executed every scan, or something like that.