Magnetic Flow Meters - Large Meter Parameter Walkthrough from AutomationDirect

Let’s work our way through the parameter menus and see what this Flow Meter can do. We’ll start with the CONFIG sub-menu because everything else depends on how you configure the device. FOU1 and FOU2 determine how outputs 1 and 2 will react in case of an error. You can have the output turn on or off in case of an error, or just leave it to do whatever the output was setup to do. Output 1 can also be a frequency output – in that case you can set the output to go to 130% of the frequency you set, go to no output frequency or don’t do anything. For channel 2 which can also be an analog output, you can set it up to go to the lower error value, upper error value or do nothing. Be careful to make sure your equipment can handle the high and low error conditions before using this option. Not all equipment can automatically handle currents of more than 20mA or greater than 10 volts. You can set a startup delay, choose if the digital outputs should behave as PNP or NPN and set a damping constant in seconds to help smooth out results. diS chooses how often the display is updated, 50, 200, 600 ms and if you want to rotate the display 180 degrees in case you have to install the unit upside down. And UNITS sets the LED display to gallons per minute or gallons per hour if you are viewing FLOW. SELd selects what you want the default display to show, Flow Rate, Total Gallons or Temperature. SEL2 selects whether output 2 should represent FLOW or Temperature. Remember – Remember Output 1 only outputs FLOW so there is no SEL1 for this unit. LFC is the flow cut off limit. This tells the sensor not to generate any outputs until the fluid flow rate is above this lower limit. That way you don’t get a lot of false readings while the system is starting up or shutting down. You can tell the total to only count net forward fluid flow or the actual fluid flow. For example, if you choose the minus and plus sign, the totals displayed on the LED will follow the actual amount of fluid that has passed through the sensor – even if some of it is in the reverse direction. If you choose this zero plus option, the totals shown on the LED will always show you the max fluid that has passed by to date and won’t show you reduced totals if some of it has passed in the reverse direction. It’s important to understand that the analog value output will always reflect the correct amount of fluid that has passed by even if there are periods of reverse flow. BUT, the digital pulse output only recognizes positive fluid flow. For example we would get pulses here during increasing volume, none during decreasing, then we start getting pulses again once the volume passes its previous max. It tells you the net amount fluid that has passed in the positive direction. And the last parameter in the configuration window is the Fluid direction. If you install the meter so that the FLOW is traveling against the direction shown on the side of the unit, then set the Fdir parameter to minus and attached the sticker that came with the unit. This parameter will make sure all the displays and outputs take the correct flow direction into account. The Memory sub-menu simply keeps track of the highest and lowest Flow rate seen to date and the max and min temperature seen to date. You can view those any time and reset them by selecting them and pressing the up or down arrows. The EPD sub menu is the Empty Pipe Detections feature. You can turn it on or off, and specify a delay time for the empty or full signal so it doesn’t trip on an intermittent air bubble. You can view the current empty pipe value and set the trip point. Once enabled, if an empty pipe IS detected, you will see this in the LED display. And we have already seen the Simulation sub menu in action so we won’t go over that again here. In the Extended Functions menu you can also do a factory reset and you can reset the gallons counter to zero yourself or tell the sensor to do itself periodically in intervals of hours days or weeks. Back on the main sub menu is where you control the behavior of the outputs. The top half is all output 1 – the digital output on this unit – and the lower half is all output 2 – the analog output on this unit. For output 1, if you select a hysteresis or window function output, these become active. The Hysteresis function turns the output on when the flow reaches SP1 and off when it falls below what ever you put in rP1. That way if you have a process bouncing around this limit you don’t get a bunch of events. The window function activates the output between the two values. That’s for when you need to make sure a process stays within limits. If you select a pulse output on output 1, then these two become active. ImPS is the volume – that is how many gallons should pass by for each pulse output? You can have a single pulse generated the only first time the meter reaches the total volume, or you can have a pulse generated every time that many gallons pass by. The Diagnostic output sends the empty pipe detection to the output. This only works if the empty pipe feature we talked about a couple minutes ago is enabled. This signal will drop low if an empty pipe is detected. Finally, if we choose output 1 to be a frequency output, these two become available. In FEP you put the max flow rate that you want to correlate with the max frequency that you put in here. Output 2 has the same window and hysteresis functionality - the set points are set in these two guys – and it has the same empty pipe diagnostic output ability as output1. The InD parameter changes output 2 to an input so it can be used to reset the gallons counter. When that is active, you can set how it works in this guy – go active on a high, low, leading edge or falling edge. And if you just want an analog output you can choose current or voltage. Everything we just did here was for the 1001 model flow meter which has one digital and one analog output. The 1002 flow meter has two analog outputs. The first output is dedicated to temperature so you scale the min and max temperatures here – that is, you put the temperature that corresponds to 0 volts or 4 mA here and the max temperature which corresponds to 20 mA or 10 Volts here. Output 2 on the 1002 unit is dedicated to flow, so you put the min and max values of the flow here. Otherwise, all the other parameters are pretty much the same as they were for the 1001 unit. If you have any questions, please contact AutomationDirect’s free award winning tech support during regular business hours. They will be happy to help. And don’t forget the forums – there are lots of folks there that love to share their years of experience. Just don’t post and questions directed at AutomationDirect’s support staff there – they don’t monitor the forums on a regular basis.