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STD924 Honeywell DP Transmitter Calibration
Need help calibrating a Honeywell STD924 differential pressure transmitter.

Hello dear friend

I have installed Honeywell STD924 differential pressure transmitter instead of damaged ABB 266MST, but without air pressure inlet the display show -67%! I use a digital multimeter as ammeter. It measure 3,81mA.(i use 02 Test terminals on STD924).

When i connect the process pipe at high pressure side of transmitter it indicate -55%.

I look at other fine process line that use fine ABB 266MST transmitter. The process value show 24%. When dismantling the measuring pipe from high side of ABB transmitter, the ABB transmitter show -11%. How to calibrate the Honeywell transmitter std924 comparing to ABB MST 266. The transmitter is connected as analog signal input to JUCO PID regulator.

ABB 266MST has LRL/URL: -10/10mbar
span limits: 0.5mbar
the sensor: 0.5 to 10 mbar
on the body of ABB sensor is written: 0 to 25.000 MMH20
STD924 SPAN LIMITS: 25mbar

other question: the Honeywel STD924 isn't write protected? as information, i don't have the HART TRANSMITTER FOR CALIBRATION AND ADJUSTMENT.

Best regards

The STD924 has a factory range of 0-1,000mbar (LRL = 0.0mbar, URL = 1,000mbar) with a 100:1 turndown for a potential minimum span of 10mbar, or 0-10mbar (LRV = 0.0mbar, URV = 10mbar).

Configuring the range depends on the exact model. Most ST3000 series had Honeywell's embedded DE protocol, which uses a DE-specific handheld (SFC/STS10x) or modem/software (SCT3000). The best bet for configuring a DE transmitter is to find a Honeywell distributor who can do it for you.

Some models can configure the range with optional HART (handheld, modem/pactware, modem/asset manager software) [HART was never standard on ST3000, HART was always 'optional', identified by a blue screw cover on the housing and HC/H6 codes in the model/part number]. If the transmitter has HART then the model number will include either code HC (means HART 5.0), or code H6 (means HART 6); again, best bet is to find a distributor with HART capability who can configure the range for you.

Some models can configure the range by applying a stable pressure reference when the transmitter is equipped with pushbuttons, identified by the code ZS at the end of the model/part number (ZS means Zero/span pushbuttons). The applied pressure when the appropriate pushbutton is pushed becomes the LRV or URV, depending (LRV is usually zero, open to the atmosphere). The pushbuttons on early models were on the top of the transmitter, on later models under the screwcover opposite the wiring end, sometimes with a local indicating meter. Pages 98-104 in the 34ST2514 manual, here:
https://www.honeywellprocess.com/library/support/Public/Documents/34-ST-25-14.pdf

The DE protocol and HART protocol are mutually exclusive, a transmitter has one or the other, it never has both.
If the STD924 does not have the ZS option, then configuring it with DE or HART, depending

Write Protection is accomplished with a jumper. The code WP in the model/part number indicates the factory enabled write protection with the jumper. The User manual has write protect on page 69 pdf. Or you can search the manuals for "write protect" for description of the jumper location and position.

The Quick Start installtion manual for the ST3000 series is located here:
https://www.honeywellprocess.com/library/support/Public/Documents/34-ST-25-24.pdf

Some info in either manual is not in the other manual, go figure.

The ABB information you provided does not define what the operating LRV and URV are for the 'old' transmitter. Yes, the minimum span is 0.5mBar, and the lower (LRL) and upper range (URL) limits are -10 to +10mBar. Knowing the limits is nice, but it isn't necessarily the range that the 4-20mA signal represents, where 4.0mA = LRV and 20.0mA = URV.

What range does the receiver Juco expect?