View Full Version : slc500 - 1746-NI16I

April 14th, 2008, 02:53 PM
Have a program running in a plc that a integrator did for one of our plants, and trying to understand it.
It is a slc500, with a 1746-NI16I 16 channel analog input card.
There is a section in the program, which I will attach, where certain bits in a channel are being referenced, that I do not fully understand, and hope someone can explain. I have downloaded the user manual for the analog card, but still not certain what the bits are.
In the attachment, there is the Mov I:1.1 into N12:21
For this to happen, one of the conditions that have to be true is labeled as I1:/285
If you put the mouse pointer over it, it shows I:1.17/13
Do not understand why he did this, it is a 16 channel input card, which I understand to be channels 0-15.
Is I:17/13, which I understand to be channel 17, bit 13 linked to input channel 1?
Will try and read more of the manual, but if someone could point me in the right direction, THANKS

April 14th, 2008, 03:09 PM
It is a channel status word for channel one for module diagnostics. Bit 13 would mean a faulty calibration. See PDF's below. Programmer does not want to use the data if calibration failed.

April 14th, 2008, 03:24 PM
Have never used a slc500 with analog before.
Most of my ab experience has been with the micrologix 1200 and 1500.
The way the analog is used is different from the slc.
Will continue to read the manual, but not exactly sure how it could fail the calibration.

April 14th, 2008, 03:40 PM
Reading more into the manual, and have the following code in the program.

Could someone explain this in simpler terms, having one of those brain dead days, reading it in the manual, but just not quite grasping it.


April 14th, 2008, 03:41 PM
forgot to post the file

April 14th, 2008, 03:44 PM
still trying to post the file.
here goes again

April 14th, 2008, 04:04 PM
On first scan of the program (powerup or Program to Run transition) the 1st rung FLL is clearing out all the old data for the 16 inputs. The COP is Writing the Configuration to the module which is stored in Integer file N10:16 to 10:31. To see what the configuration is, you can compare those 16 words to the manual.

The 2nd rung runs continously and is copying the Status Words for each input channel into an Integer file N12:40 to N12:55 for use elsewhere in the program.