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Topics - TravisB

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Technical support / Writting data to local PC
« on: August 08, 2012, 11:30:22 AM »
I see that ExcelLink is the easiest method to get data off a PLC and onto a PC, but requires Excel be on the PC. I don't want to us the Email method because, as I understand it, I'd end up with a new email every hour when really I want to appened to an existing file. I get the impression that there are other methods as well, but I don't understand the jargon to know which one (Modbus, Multi-point, Host Link Protocol) I should spend my time learning about. I've read those chapters and I will need to spend a lot of time on wikipedia and elsewhere learning what all those words mean before I can proceed.

I have an onsite PC connected to the f1616-ba PLC via ethernet cable. It is dedicated to runing several operations and is expected to be "On" at all times, running TLServer. I would like to have the PLC initiate communication and send many DM fields to a location on the PC. Hourly, and appending to an existing file.

Where should I be looking?

2
Technical support / Program execution takes longer than Clk:1.0 Clock?
« on: May 09, 2012, 04:34:43 PM »
I have a program that runs alright in the simulator, but not on the PLC(F1616-BA). I have 5 functions which run on the CLK:1.0s every time, State independent. There are some loops in there and a reading of 3x I-7017 over RS485. I also run an adaptation of the HMI sample code which runs every CLK:0.1 when State 1 is active.

One problem is that I'm not getting any reading from the I-7017s, even with a few sensors attached which work when the PLC is running the (much smaller) I-7017 sample code altered to read three 7017s at a time.
I also find that the HMI keystrokes require an unnaturally long depression of the key before they register, and then stay registered for a moment.

I was trying to think how I could have taken working code and corrupted it during cut/paste when I noticed that a variable which should increment every 0.1sec (off CLK:0.1s), was in reality incrementing much slower than that. After 60 seconds in real time, the counter represented 11 seconds. This makes me wonder if my code is causing the PLC to be in mid-execution of some part of a function when the CLK:1.0s forces it to go elsewhere. Or, just as bad, that the PLC continues what it's doing and ignores the request from the CLK:1.0s.

Can you please help me narrow down the possibilities?

Edit: improve clarity and spelling

3
Technical support / Are there limitations to DM significant digits?
« on: April 03, 2012, 01:51:14 PM »
I am using an FMD series PLC to read a pressure sensor. In order to get the number of significant digits I need for accuracy, I have to use very large numbers (1,000,000.) My proceedure works when using "letter variables" but not when using DM[] variables. I thought there might be a limit to the number of significant digits for a DM[] variable, but I can't find any mention of this, so now I'm confused.

Sample:
'---Read Main Tank water level
A = ADC(1)       'Tank sensor raw output
DM[11] = ADC(1)
'Calibrate the reading
'These sensors output values on the order of 1000 / foot,
' so to get acuracy of 1/10th of a foot we need to convert to
' 1/1,000,000 to calibrate, then convert back to 1/100th of a
' foot before moving on in the program
B = 2658             'Slope (1/1,000,000 feet)
DM[12] = 2658
C = -2120000             'Intercept (1/1,000,000 feet)
DM[13] = -2120000
D = B * A + C     'Calibrated water level (1/1,000,000 feet)
DM[14] = DM[12] * DM[11] + DM[13]
'Convert back to 1/100th using MOD to trim unwanted sig.dig.
DM[100] = (D-(D MOD 10000))/10000
DM[101] = (DM[14]-(DM[14] MOD 10000))/10000
DM[102] = ((DM[12] * DM[11] + DM[13])-((DM[12] * DM[11] + DM[13]) MOD 10000))/10000
D = DM[100]       'Calibrated water level (1/100 feet)

"D" gives me the correct value, DM[101] doesn't get calculated, and DM[102] returns an incorrect value. (They should all be equal.)
Do DM[] variables keep fewer significant digits that "A, B, C" type variables?

4
Technical support / Way to advance the time/date in the simulator
« on: March 23, 2012, 03:43:13 PM »
I have some BASIC code which takes action based on the change of day, and month, and year at midnight each day. I'm wondering if there is a way I can run the simulator and advance the date/time to midnight, to the end of the month, and to the end of the year so I can see if all of my actions are occuring as expected.

5
Technical support / FMD88-10 with SSI Media Sensor
« on: March 09, 2012, 02:38:13 PM »
I have an FMD88-10 with a simple program running successfully. I have attached an SSI P51 3PSI Gauge pressure sensor.
I have the senors set-up to calibrate with the positive (red) going to the AC/DC transformer, the ground (black) going to the analog ground (0V (gnd)) and the white wire going to AD2.

When the pressure applied to the sensor changes (increases or decreases) the sensor reacts appropriately, but then slowly returns to the same reading from before the pressure change.

I have in the past worked with Druck pressure transducers with Campbell Scientific dataloggers. My assumption was that the present set-up would work similar to the previous set-up I have experience with.

If this is all explained in the archives feel free to point me in the correct direction. I've tried searching, but havn't found anything yet.

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