Hartech

Hey all, Further to my other post I need to read an analog input flowmeter signal (4-20mA) and scale it to litres per minute flow-rate. Then display on HMI...... Then use a PID control block to control a output water control valve (4-20mA) to a calculated set point (litres per minute) The flowmeter is measuring water flow in a pipe & The control valve is controlling the flow rate in the pipe. The water is then sprayed onto a conveyor belt - measured at a percentage SP depending on the amount of powder product on the conveyor belt (in KG) 1. So inputs to PID is the SP (litres per sec) calculated every few seconds from product weights (kg) in bins. 2. And the PV is the flowmeter reading. 3. Output is the control valve (4-20mA) Does anyone have any tips to do this or some good flow PID and flowmeter example. Your help would be much appreciated. Thanks Richard

Hey, I have a project which one part involves using a RTD PT100 (0-100 Deg.C 4-20mA) connected to a CJ1W AD041 (ATD input card), the PLC is a CJ2M Basically the PLC needs to read the RTD and display the temperature on a Omron HMI (NS10), via Ethernet, Could someone please help me out with a basic example program - to read and convert the RTD - ATD value to store in memory. Your help would be most appreciated. Thanks Richard

Thanks for the tips - yes this is an option - I will look at the options of linking the analogue inputs and outputs of the drives - and possibly use the built-in PID of one drive to act as a master/slave to the other drive - so the slave will 'follow' the analogue actual speed reference output from the master drive - only if this is possible? - need to dig deeper to see if the analogue output is a true speed reference of the motor - i.e it's not a true closed-loop feedback control like an encoder. The Altivar™ 312 drives used in this project don't allow for the connection of a rotary encoder for feedback- only the larger more advanced drives have this option. Thanks

Thank you for the information - I will look at implementing this.

Thank you.

Hello, I need to Synchronize two 4kW motors connected to their own individual AltiVar VSDs. To put it simply the two motors are pulling cables on a pulley and when loaded the motor's slip and the speed varies. I have an Omron CP1L-EM PLC and 2x Omron Rotary Encoders ( E6C2-CWZ5B encoders - 360 PPR) - connected to each motor, What is the best way to read the pulses from the two rotary encoders then convert to RPM? 1) Using PRV or PRV2(883) instruction, - this would be the best option as it would convert the value to RPM - however, can I use this instruction on both Counter 0 & Counter 1? 2) Or read the raw value from Counter 0: A270 (connected to motor one's encoder) Counter 1: A272 (connected to motor two's encoder) Convert the pulses to RPM - then compare and adjust? 3) Or using CTBL. - is this a useful instruction for this application? Once I get the RPM speed from each motor - I can then do a compare instruction - see if there is a mismatch and if so send a scaled analogue output to the VSDs to correct the speed if required. (10-50Hz) What would be your recommendations? any help would be most helpful. Thank you.

Hello, Could you please provide an updated link to the Counter example.cxp file - this link is broken. Thanks