Maintpro

I have several machines connected to a DH485 network. I would like to access this network via the company LAN/internet. What needs to be done to accomplish this?

Our Q.A people only care that the scales are calibrated (by outside sources) and have a sticker indicating calibration date and next due date. The have never come out and tested any packages. As far as they are concerned, the system is working if it passes calibration and they do not receive any complaints as far as weights go. They are however, the first ones to dictate in what kind of divisions we can measure in. Pretty good quality system eh.

You are right and I do not want to just hide this problem. The thing is though that there is a lot of floor vibration from heavy mixing equipment and there are roller conveyors mounted to the top side of the scale bed. I can eliminate the fluctuation through filtering and sampling but the excessive filtering and samples slows down the scale response and I will overshoot my upper setpoint. As it is, We have seven scales in the process and this is the first of those that we have switched to be a plc based system. The remaining six scales read in divisions of .05lbs as well.

Doesn't the result end up being back into .01 divisions. Lets say my weight reading is 50.03 lbs. 50.03 x 20 = 100.6. As an integer it is 10006. 10006/20 = 500.3 This is basically where we began. To scale this back down 500.3/10 = 50.03. Am I missing something here. I was hoping that we could convert this into, in this case, 50.05. This would be rounded out to make my .05 divisions.

I am installing 1746-ws load cell modules in my micrologix 1500. The connecting scales are used in a high speed batching process. The resulting weight readings from my scales are displayed down to .01 lbs. The problem I have is that I am unable to stabilize my weight measurements enough to pass calibration. (Excessive filtering and sampling slows the system down too much and I overshoot my high setpoints.) Calibration for trade requires an accuracy of +/- one division, which in my case, is +/- .01 lb. I can stabilize my reading with additional math and achieving a reading down to .10 lbs. This does not satisfy Q.A because my old (non plc based) scale systems displayed down to .05 lbs and Q.A feels that the accuracy of the new system is not the same when displayed in .10 lb divisions. If I could convert my .01 divisions into .05 divisions my system would pass calibration and Q.A would be satisfied. Any suggestions on how to accomplish this?

30 views and no replys. What gives? Doesn't anyone have an opinion on what could be causing my temp issues? If this was viewed by all in the other forum then I appologize for being upset. I am not very familiar with PID operation and am just looking for answers.

I am having problems with the PID operations of my SIMATIC 545 PLC. We use the controller in a wax melting operation. The wax kettles are heated by steam and the PID is adjusting the valve position. The valve position range is -25% to 100%. The problem is that when the PV is the same or greater than the SP, the the valves are occasionally still open 50% or sometimes greater (I say occasionally because it is not every time). This leads to overheating of the kettles and burning of the wax. If we turn the steam off (this takes the loop out of auto) and then back on again, the output will correct itself. We have had this system in place for a number of years now and according to the operators, it has never worked properly to begin with. My loop perameters are as follows: POS/VEL PID ALGORITHM: POS LOOP VFLAG ADDRESS: C702 SAMPLE RATE: 2.00 SEC PROCESS VARIABLE ADDRESS: WX177 PV RANGE LOW: 0 HIGH: 300 PV IS BIPOLAR: NO SQUARE ROOT OF PV: NO 20% OFFSET ON PV: YES RAMP/SOAK PROGRAMMED: NO RAMP/SOAK FOR SP: NO ALARM DEADBAND: 0 MONITOR LOW-LOW/HI-HI: NO MONITOR LOW/HI: NO PV ALARMS LOW-LOW: 0 LOW: 0 HIGH: 100 HIGH-HIGH: 100 REMOTE SETPOINT: NONE CLAMP SP LIMITS LOW: O HIGH: 300 LOOP GAIN: 50 RESET: 35 RATE: 0 FREEZE BIAS: NO DERIVATIVE GAIN LIMITING: NO LIMITING COEFFICIENT: 10 SPECIAL CALCULATION ON: NONE SPECIAL FUNCTION: NONE LOCK SETPOINT: NO LOCK AUTO/MANUAL: NO LOCK CASCADE: NO ERROR OPERATION: NONE REVERSE ACTING: NO MONIOR DEVIATION: NO DEVIATION ALARM YELLOW: 100 ORANGE: 100 MONITOR RATE OF CHANGE: NO RATE OF CHANGE ALARM: 0 MONITOR BROKEN TRANSMITTER: NO This is the first time that I have had to deal with a PID system and am uncertain if these perameters, especially the gain, are correct. I am also wondering if the problems are due to fluctuations in the process variable and if I should freeze this value for loop use by moving it into a V-register. I have monitored the program and found that temperature values received by the plc are correct. Any help you can provide would be greatly apprecieated.

I recently got a new laptop and am running Windows XP. I am now having problems maintaining communication with my FX2n plc. I have an old version of the FXGP/WIN software (V1.10) and am wondering if there is a newer version available and if upgrading will solve my problems.