Noobie question

Hi, I have been given task to solve operation of a machine controlled by an Allen Bradley SLC 5/01. Machine has been operated " out of sequence" which has resulted in several OTL being latched without any way of being unlatched stopping machine from running. Is it possible to unlatch all the OTL's (as initial startup) without communicating with the PLC?
I presume that if this is not possible, I would need: laptop running Rslinx, Rs500 Logix, 1747-UIC and 1747-C13 cable.
Going online with plc, I assume that the latched outputs can be forced to unlatch?
Dave

Does the machine have an HMI? If so, what type? Some can address registers directly.

HMI? Is this human interface? No. Machine control panel has various operation switches and indicator lights. Two indicators denote latched parts of program which need to unlatch but this can only be done by illogic timers, counters and other latched OTL's. I only have printed ladder logic which was done in 1996 no changes to ladder logic have ever been done. There are some bugs in ladder but can be overridden manually. It is complex ladder of 300 rungs.

You are correct: you will need RSLogix 500 development/editing software, the RSLinx Classic Lite communication driver software, and the related 1747-UIC and cable.

Once you're online, you'll be able to highlight the incorrectly-latched memory bits, right-click, and select "Toggle". Or you can open the data table view and put a zero in the desired address.

black bear said:

Is it possible to unlatch all the OTL's (as initial startup) without communicating with the PLC?

Click to expand...

Yes. You'll need to do as Ken Roach advises to be able to go online with the processor. Then, add some logic which can set the latches at startup (by this I mean powerup) - or at another time by designating a switch/bit for the purpose.

Thanks for replies, ordering hardware tomorrow, ~ £300. Hope comm's goes ok, I've heard that it can be tricky, i.e. Setting up correct drivers.

Setting up comms is not to difficult..just follow the instructions to add drivers in rslinx