Read MSG Instruction with Timers

All,
We are developing MSG instructions with ControlLogix; this controller is the master data collector for the plant.

However there are some antique applications in the field that we do not have access to change.

The data that we need is in the form of a timer DN bit residing in a SLC 5/03 which drives an output.

If we could access either the DN bit or status of the Output data file we would be set.

Is this even possible, I have gone through the AB/Rockwell manuals and have not found anything like this.

Any help is much appreciated.

What is your access to the SLC-5/03; are you using a 1761-NET-ENI to the Channel 0 serial port, or are you putting a 1756-DH485 module into the ControlLogix ?

I have only ever read and written N and R data files from Logix -> SLC. The ControlLogix MSG instruction rejects Tx:y.z and O:x.y addresses with "Invalid Remote Element".

It does not, however, reject the otherwise invalid address "N4:0". I don't think that will work, though, because it's a "Typed Read", which includes a byte that designates the Data File Type (N,B, T,C, F, etc).

You might be able to use the "PCCC Object" in the Net-ENI. Tell us more !

Ken,
You are correct we are using a NET-ENI.
So everything we are trying to do is via MSG instuctions over IP.

Again you are correct anytime we setup an Tx:y.z or O:x.y it does not like it at all.

I will take a look at the PCCC object.

The way the PCCC object works is that you send a CIP Generic message to the device (I've done this mostly with the Net-DNI) whose data payload is an encoded PCCC command.

This lets you send command that the MSG instruction can't natively perform. You can, for example, perform a PROG->RUN transition or EEPROM burn or Memory Clear on a controller connected to one of these devices, if you so desired.

You can also mess it up pretty good; I managed to fault a MicroLogix 1000 just playing with the feature.

Interesting, guess I better step lightly.
We began looking at mapping the SLC messages under tools RSLogix didn't know if that would be a waste of time. The only other alternative I can think of is using a ProSoft module or something. We're kind stuck between a rock and hard place. Thanks for you advice.

PCCC Object in Net-ENI

Man, I love an undocumented challenge.

The best documentation on the PCCC Object is actually in the 20-COMM-D User Manual. The CIP service is 0x4D, Execute Local PCCC, and you direct it as a Generic CIP Message to Class 0x67, Instance 1, Attribute 1.

The data payload should be a 9-byte SINT array. I used:

0F 00 00 01 A1 06 04 86 00

The arguments for a SLC Typed Read (function code 0xA1) are Data Length, Data File, Data Type (0x86=Timer), Element Number.

The reply included six data bytes, which are the Flag word, the Preset Word, and the Accumulated Value Word of the timer.

4F 00 00 01 00 c0 f4 01 8a 00

Timer T4:0 Flags: 0xC000 = 1100 0000 0000 000 = /EN and /TT bits set
Timer T4:0 Preset: 0x01f4 = 500
Timer T4:0 Accumulated Value = 0x008a = 138

Attached is a quick and dirty example in RSLogix 5000 version 15.

Undocumented indeed, man this brings back some bad DeviceNet troubleshooting memories.

Question this would be the Timer Timing and Done bit, I thought the 13th bit was the enable?
Timer T4:0 Flags: 0xC000 = 1100 0000 0000 000 = /EN and /TT bits set

Thanks again Ken, I will post our results after we test it.

Malign not my beloved DeviceNet !

I had to go to the source to remind myself of the bit pattern for an SLC's control word. From the 1747-RM001 Instruction Set Reference, page 1-5:

Word 0 Control Flags
15 EN
14 TT
13 DN

Word 1 Preset Value (PRE)
Word 2 Accumulator Value (ACC)


The remainder off the control flag word is unused or marked "internal use". I know the timebase is encoded in there.

Ken what is the PCCC & CIP stuff. I like to learn new stuff.

PS The MLX1500>DNI>PV600 that we talked about is still kicking my backside.

HaHa! Fair enough I should clarify the DeviceNet troubles were due to my own ignorance. Nonetheless still painful.

JeffKiper said:

Ken what is the PCCC & CIP stuff. I like to learn new stuff.

PS The MLX1500>DNI>PV600 that we talked about is still kicking my backside.

Click to expand...

Until Ken checks back in, here is a link to one of his post about the two protocols above. ( click on the link he provided)

http://www.plctalk.net/qanda/showpost.php?p=306167&postcount=2