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Kep Flow Meter Totalizers: Programming Smart Electronic Rate Monitors and Batch Controllers via Modbus
Quick Answer: KEP flow meter totalizers are smart electronic rate monitors and batch controllers. They read pulse or 4-20 mA signals from a flow meter and expose rate, total, and batch values over Modbus RTU or Modbus TCP. Set the slave ID, baud rate, K-factor, and time base before you poll any register.
What a KEP Totalizer Does on a Flow Skid
KEP flow meter totalizers are compact rate monitors and batch controllers. They take a raw flow signal and turn it into a rate display, a total, and a batch output. In most installations the flow meter sends a pulse output. Each pulse represents a fixed volume. The totalizer counts pulses, applies the K-factor, and shows total volume. For batch control the same unit opens a valve, counts volume, and closes the valve at the preset.
Silver Automation Instruments supplies flow meters that connect directly to these totalizers. Our electromagnetic, oval gear, turbine, and Coriolis meters can send pulse or 4-20 mA output. Some Coriolis models also provide 4-20 mA HART output for density and temperature. A water treatment plant in Malaysia runs an electromagnetic flow meter DN80 with a KEP totalizer. The unit polls rate in m³/h and total in m³ over Modbus RTU. The K-factor comes from the flow meter calibration sheet.
How KEP Flow Meter Totalizers Use Modbus Registers
Do not assume every KEP model uses the same register map. In practice, most rate and total values sit in holding registers. Function code 03 reads them. Function code 06 writes a single register. Function code 16 writes multiple registers. A typical KEP totalizer map may look like this.
Holding register 40001 is rate. Holding register 40003 is 32-bit floating point total. Holding register 40005 is batch total. Holding register 40007 is batch preset. Holding register 40009 is flow input type or decimal point. Coil 00001 starts the batch. Coil 00002 stops the batch.
Some PLCs read the floating point registers in the wrong word order. If the value looks like 1.38E-23 instead of 125.6 kg/h, swap the high and low words. Check the KEP manual for the exact register list and byte order. Modbus RTU usually runs at 9600 baud 8N1. Modbus TCP uses port 502. Set the slave ID before you connect more than one device. Duplicate slave IDs cause Modbus timeouts that look like wiring faults.
Programming Rate and Total Values on KEP Units
Set the flow input type first. A pulse input with a K-factor of 100 pulses per liter is different from a 4-20 mA input scaled 0 to 5000 kg/h. Then set the rate time base. Choose seconds, minutes, or hours. If the time base is wrong, the rate will be off by a factor of 60.
The K-factor is the most common source of error. A food factory in Vietnam batches syrup with an oval gear flow meter. The KEP unit was configured with pulses per gallon instead of pulses per liter. The batch overshot by 20 percent. The fix was simple. The K-factor field was corrected from 378.5 to 100 pulses per liter.
Totalizer decimal point and rate decimal point are separate settings. Set both. If the total is 1500.0 liters, do not display 15000. A chemical plant in Indonesia wasted half a day because the total decimal point was set to one extra digit.
Batch Controller Programming Sequence
Set the batch preset in the KEP unit or write it from a PLC over Modbus. Use holding register 40007 as the preset. Start the batch with coil 00001. The controller opens the valve and counts pulses.
For batching in hazardous areas, use a flow meter with ATEX Zone 1 approval and isolate the Modbus wiring. A paint manufacturer in Southeast Asia uses a Coriolis mass flow meter with a KEP batch controller. They batch solvent at 300 kg per batch. The PLC writes the preset over Modbus TCP and reads the batch total back for traceability.
Wiring and Signal Input Notes
Use shielded twisted pair cable for RS485 Modbus RTU. Connect A and B correctly. Install a 120 ohm termination resistor at the last device. Keep the cable away from variable frequency drive cables. Most engineers skip this part. They wire RS485 without a termination resistor. Then Modbus polls drop out at 9600 baud.
Pulse input is more accurate for totalizing than 4-20 mA because each pulse has a fixed volume. But 4-20 mA is easier to scale for rate. For fast batch cycles under 10 seconds, a pulse output from an oval gear or electromagnetic flow meter works better than 4-20 mA.
For clean water with conductivity above 5 µS/cm an electromagnetic flow meter is a good fit. For high viscosity fluid up to 1000 cP an oval gear meter gives better pulse resolution. A thermal mass flow meter with a PT100 sensor can output 4-20 mA for gas flow rate. Silver Automation Instruments can pre-configure the flow meter pulse output to match your KEP totalizer. Send us the K-factor, pipe size, and batch size. We will set the pulse output frequency so the totalizer counts correctly.
FAQ: KEP Flow Meter Totalizers and Modbus
Can a KEP totalizer read Modbus directly from a flow meter?
Most KEP totalizers read pulse, 4-20 mA, or serial input depending on the model. If the flow meter has Modbus RTU output, some KEP models can read it as a slave. Check the input option code before you order.
What Modbus function code changes the batch preset?
Function code 06 writes a single holding register. Function code 16 writes multiple registers. Batch preset is often a 32-bit floating point value, so write two registers at once.
Why does my KEP batch controller overshoot the preset?
In most cases the K-factor is wrong or the valve close time is longer than expected. Correct the K-factor and set a pre-stop value 2 to 5 percent before the final preset.
Which flow meter signal is better for a KEP totalizer, pulse or 4-20 mA?
Pulse is better for total and batch accuracy. Use 4-20 mA when you only need rate display or when the control system already has an analog input card.
Do Silver Automation Instruments flow meters work with KEP totalizers?
Yes. We supply electromagnetic, oval gear, Coriolis, ultrasonic, vortex, and thermal mass flow meters with pulse or 4-20 mA outputs. We can match the K-factor and output type to your KEP totalizer.
Get a Flow Meter and Totalizer Quote
Send your pressure (bar), temperature (°C), pipe size (DN), flow range, and batch size. We will recommend a flow meter and totalizer combination. Contact Silver Automation Instruments at Tel: +86-25-68650347 or Whatsapp: +86-25-52155837. WeChat: +86 15365082610. You can also visit flow-meter.com.au.
Do not send a request like "need flow meter price" without the process data. A quote request without pressure, temperature, pipe size, and flow range adds two or three email cycles. With those four values we can usually reply within one working day.
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