enabling the SLC card with Output

Hi there,

This is a simple question. I am using a SLC to control a ArmorStart trough DeviceNet. I am connected and setup correctly the parameters of the ArmorStart and the scanner. I already mapped the Armorstart but when I started making a simple program to control the Armorstart in Rslogix 500 I wasn't able to Start the motor with the respectively output. A technician told me that I had to add a rung in my program enabling the first word first bit of the outputs in order to enable the SLC card and this actually solved my problem. I didnt really understand what he was talking about I tried to find it in the Manual but I couldnt.

I attach a photo of my program and Maping.
Regards

The 1747-SDN DeviceNet Scanner Module, like all other DeviceNet Scanner modules from Allen-Bradley, has a command word that you can use to control the basic functionality of the module, including placing it in RUN mode.

When the module is not in RUN mode, you get a status code 80 on the module's 2-digit display.

If you're looking for a specific reference in the User Manual (Publication 1747-UM655), setting Word 0/Bit 0 in the 1747-SDN Output to TRUE to enable run mode is described on page 86.

Memory lane: "80 = SDN Idle" was literally the first thing I wrote in my spiral notebook on my first day working at Allen-Bradley in November of 1996.

Ken,

Sorry to but in. Just a quick query...

I was working on a 1769-SDN last night. I had to flash the firmware as there was a bug with v2.2 not allowing a download to the scanner when the scanlist had a device mapped for greater than 128bytes I/O. I have a device that I wanted to expand from 32bytes I/O out to its max. of 240bytes I/O. The updated firmware allowed a successful download, yipee.

Anywayyyy...

Between all the "80" "01" "78" "01" "77" "01"... and whatnot errors i was constantly getting at various times on the scanner, I would always only have to set the PLC (1769-L32E) back into RUN Mode to reset the "80" IDLE to "00" Running status.

It's been a long time since I worked on a 1747-SDN and was wondering if it's not the same? Do you have to set that bit in the control word to place the scanner in RUN Mode or will a processor RUN cycle do the same "trick"?

I haven't time to look it up. I'm just finishing a late shift and heading home soon. I was just curious in passing as I'd just dealt with similar last night.

Regards,
George

Actually, a thought just occurred to me...

It's not my program, originally, although I have made extensive mods to it. It is possible that the fact I'm going to RUN Mode simply means there is logic somewhere writing a "1" to an equivalent Run bit for the scanner? Something I'll have to confirm tomorrow.

It was an off the cuff query. I hadn't thought too deeply into it before posting. I just assumed from last night that the scanner just needed to see the processor in RUN Mode for it to go to Run?

Hmm...

In general, you must both have the DeviceNet Scanner's output word RUN bit = 1 and have the controller in RUN mode for the DeviceNet Scanner to go into RUN mode.

I've seen plenty of systems where somebody just poked a 1 into the Output data table, but I always put it into my logic with an interlock to the E-Stop status input. That's not to attempt a safety stop over the network (I hardwire power to devices that need to turn off in that state), but rather just to be sure all my devices go into a predictable state.


To my knowledge there is no requirement for a change of state (0-> 1) for the RUN command bit nor a transition of the controller from PROG to RUN, though a system immediately after a firmware upgrade may be an exception.

Nope, it appears, as you said, that all scanners have one. The 1769-SDN has the same Run bit at Word 0/Bit 0, similar to the 1747-SDN.

I just could not ever remember having manually poked a 1 in there, let alone programmatically setting it, on previous jobs. But I must have done one or the other?

It's been a few years since I did one from scratch, so I'm a bit hazy on this aspect of it.

I'm back in early tomorrow, so I'll check then what the original programmer did for the project I am working on.

Sorry for the distraction!

G.

Just to wrap this up...

The original programmer had indeed just poked a "1" into the scanner's Run bit and it's been automatically going to Run every time the processor is put into Run Mode. So you do not need to cycle the scanner's Run bit at all, once it's been "initialized". Whether you should cycle it under certain conditions is another matter.

G.