I need equipment for converting a pulse/frequency signal from a flow meter (compound for waste water flow) to MODBUS RTU SLAVE Protocol.

 

I suggest a simple PLC, setup as a Modbus slave and equipped with a HSCouster (if required , depends on the frequency of the input signal). Use the PLC counters to calculate the flow signal, place the result in a register and send the register to a modbus master when requested. I can suggest a S7-200 CPU from Siemens; not expensive, the S7-221 has integrated power supply, 6 inputs (of which 2 can be set-up as HSC) and 4 outputs, and there is a program block you can install that uses the programming port in a Modbus slave mode. There are probably many other alternatives available on the market.

Hope this helps,
Daniel Chartier

 

Hi,

I would use a Siemens S7-200 with a small program to convert the pulse train to required units, then use the modbus library to configure the serial port as MODBUS SLAVE.

Marc Sinclair
http://www.germainesystems.co.uk

 

I think you should take a look at this </b>
http://www.controlmicrosystems.com/products/scada/scada_packLP.html.

This is like a plc but use for gas and flow monitoring. Modbus protocol is native.

Hope this helps.

 

It is possible to convert frequency/pulse to MODBUS by the Universal Frequency-to-Digital Converter (UFDC-1): http://www.sensorsportal.com/HTML/E-SHOP/PRODUCTS_4/UFDC_1.htm

Normally, the UFDC-1 (standard version) is working with SPI, I2C and RS-232. So, you need ask about custom design for MODBUS.

- End -

 

Please visit http://www.renuelectronics.com and see flow products.

Best regards,

Santosh

 

Take a look at MOX Products MOX603 I/O Counter/Frequency module. It supports up to 100kHz, has 4 individually isolted quadrature input channels that can be configured individualy for continous counting, periodic counting and frequency measurement plus enhanced functions such as high/low frequency alarms. The standalone MX603I/O modules support Modbus RTU communications via the ethernet port, 2 RS485 ports and 1 RS232 port.

Regards
Conrad van Rooyen
MOX Products
www.moxproducts.com

 

dae manufactures amr module, which can measure 16ch pulses from water meters and acculumated then convert to modbus rtu ; module also equiped led data display counter to view datas.
http://www.daeinstrument.com

this module has eeprom to store counter data even power interrupt. and a software filter is desined to reject abnormal pulse signal like bump or electric interfenernce signal.

 

I have several facilities offshore that all use Control Microsystems PLC units. Using the "flow" block and a counter input, the plc will store up to 35 days of counts. Many of the systems have been in service (accumulating oil / water) for over 6 years.

It is VERY easy to configure and works without a hitch.

Wade Artigue

 

Argolo,

What is the brand and model of the flow meter?

 

Hello Marc,

Acromag manufactures a Model 942MB-0900. This is a Din Rail mounted, 2 channel Frequency/Pulse to RS485 Modbus RTU slave device. Acromag also makes a Frequency/Pulse Counter to Ethernet Modbus TCP/IP (reference Model 989EN-4016).

Here's a link to the 942MB product:
http://www.acromag.com/parts.cfm?Model_ID=268&Product_Function_ID=28&Category_ID=9&Group_ID=2

Datasheet: http://www.acromag.com/pdf/942mb.pdf

If any questions or we can assist further, please let me know.

Kind Regards,
Donald Lupo (dlupo [at] acromag.com)