Wondering how to "defeat" the left hand most timer in Logixpro I/O simulator

Wondering how to "defeat" the left hand most timer in Logixpro I/O simulator

Wondering if any one can help answer the attached two questions.

I've already set a repeating timer that has the accumulated value of the timer displayed on BCD display, but now i'm having trouble figure out the next two questions.

Any hints or how tos would be apperciated!

Welcome to the forum!

The "Masked Move" the question refers to is the MVM instruction. Drop one of those into the code, select it, and press F1. Read through the help file on how it works and what it does - that should give you an idea of what your instructor is hinting toward. Have a crack at implementing it, and post back if you get stuck!

Thanks,

I have tried it out, but i'm really at a dead end on where to start with the MVM, i've attached it to the program but really not understanding how overcome the left hand thumbwheel with the MVM command.

Well, if I understand the question correctly, you've got four thumbwheel switches, each giving you a BCD value inside the PLC.

0000...9999

If the right-hand one is set to tenths of a second, then you can set any number from 000.0 to 999.9. You need to convert this from BCD to decimal, and move the value into your timer. My first tip is to revisit your logic slightly, and try to perform these operations in that order. You'll find it much simpler from there.

Once you've done that, you can approach the next part of the question: allow only values from 000.0 to 099.9. You want to block the first digit from having any effect. So, you need to strip out the data from that first thumbwheel, and move only the remaining three digits into your timer.

Two questions you can hopefully answer:

1. Should you strip the first digit out of the data BEFORE or AFTER you convert the BCD to decimal?
2. How might you use a MVM to move only the part of the data that you require, while masking the rest?