1.1. GF 2551 Magmeter jumper settings

The GF Signet 2551 magnetic flow sensors can be set to communicate with the 9900 or 9950 controller using either frequency, or in S3L mode. S3L mode allows the sensor to register the direction of the flow. In the case of a filter flow meters, sensors set for directional flow measurement will display normal flow in positive numbers and backwash flow in negative numbers.

The second jumper is used to select the correct pipe size range for the sensor. (See fig 1). The correct K-factor for the pipe size and type of installation fitting must also be selected during setup of the controller/transmitter if equipped.

When setting up a new sensor, or when converting one to S3L, you will need to set the jumpers on the sensor circuit board. This board is located under the display module on the display equipped 2551 magmeter. For the 2551 blind magmeter it is below the sensor housing cover.

IMPORTANT - Do not adjust the jumpers while the sensor is powered. Doing so can cause permanent damage to the sensor.

 

FIG. 1. Jumper settings for 2551 magmeter.

 

 

1.2. GF 2551 Open Collector Output Wiring

Here's an example for wiring a GF Signet 2551 blind magmeter's frequency output (open collector style) to an Opto 22 IDC5 module.

The GF Signet 2551 open collector output works from +5 to +24 VDC.  Use +24 VDC to be well within the Opto 22 IDC5 input range (+10 to +32 VDC).

 

Install an isolated +24 VDC power supply.  Wire  + and – to terminals 1 & 3 on the 2551 as shown.  Add a 10 k-Ohm resistor (1/2 watt will suffice) between terminals 1 & 2.  Wire the 2551’s Frequency Out to the + side of the IDC5 and the 24 VDC power supply’s negative to the minus side of the IDC5. 

 

Note that the IDC5 has a theoretical max frequency measuring capability of 100 Hz, probably lower in reality (I can’t find the specs).  If the flow measurement frequency exceeds 100 Hz we should look at the Opto 22 IDC5B  (which of course would require a different power supply, nominally 12 VDC)

 

 

 

 

Polarity for the IDC5 module

 

 

 

Note this can also be applied to other I/O platforms and other flowmeters with open collector outputs, e.g. GF Signet.  This method is not applicable for the sine wave frequency outputs of some flow meters, especially ones that are amplitude based.

Compatible flow meters per 41st edition GF Signet Measurement and Control Product Catalog:  2000, 2100, 2507, 2536, 2537, 2540, 2551, 2552

In RCK's experience this has worked for 2536, 2537 and 2551 flow meters.