Brand: Palmer Wahl

Palmer Wahl DST600 DST640 Digi-Stem RTD Thermometer

Name: Palmer Wahl DST600 DST640 Digi-Stem RTD Thermometer
Brand: Palmer Wahl
SKU: Palmer Wahl DST600

Description

A digital RTD thermometer system for temperature critical processes

The Palmer Wahl Digi-Stem DST600 and DST640 series is a digital RTD thermometer system: a battery-powered meter with a large 1 inch LCD, plus a Pt100 probe built to order. The DST640 differs from the DST600 by its laser welded stainless steel case and H-frame, which the datasheet describes as extra protection against RFI and water ingress. Both are designed and built to order in Asheville, North Carolina.

The datasheet says the series meets and exceeds the FDA Final Rule 21 CFR Part 113 and meets USDA 9CFR318.305 for canned meat and 9CFR381.305 for canned poultry products, and calls it ideal for low acid canned food processing in hermetically sealed containers. Those statements are quoted as printed on the datasheet; confirm the approval scope for your own installation.

Features

Self-checking technology continuously verifies the electronics and shows Err on the screen when a reading is out of tolerance.
Probe ID: only the probe whose ID is programmed into the meter can be read; another probe shows Prb on the screen. It can be disabled at the time of order.
Calibration software DSTCAL, sold separately, is required for any adjustment, which makes the meter tamper resistant.
24-bit delta-sigma analog-to-digital converter, with checks for open sensor wire, under-range, over-range and low battery.
Quick disconnect at the meter end, the probe end or both, so the probe and meter can be calibrated as a system without removing a permanent cable.
Probes use Pt100 Class A four-wire platinum RTD sensors in magnesium oxide packed mineral insulated cable; sanitary probes comply with the 3-A Sanitary Standard.
Direct replacement for bimetal, bulb and capillary and mercury-in-glass thermometers.

DST600 and DST640 specifications

Parameter	Specification
Sensor	Pt100 Class A, 4-wire RTD; R0 100 ohm, alpha 0.00385, serial ID chip
Meter range	-50 to 500 F (-45.5 to 260 C), selectable F or C
Meter accuracy	Plus or minus 0.1 F/C over 1 year at 23 C plus or minus 5 C
System accuracy	Greater of plus or minus 0.3 F / 0.2 C or plus or minus 0.5 percent of reading, over 1 year at 23 C
Ambient operating range	-40 to 158 F (-40 to 70 C); 10 to 100 percent RH non-condensing
Temperature coefficient	Maximum 0.003 per C from 23 C plus or minus 5 C
Vibration	MIL STD 202G method 201A extended to 60 Hz, 10 to 60 Hz
Display	1.0 inch 4-digit LCD, readable from 30 ft; resolution 0.1 below 1000, 1 at or above 1000; optional R model 1.0 or 0.1
Update rate	2 s default, adjustable 0.25 to 10 s with DSTCAL; I model 3 s
Battery	One C-size lithium thionyl chloride 3.6 V, user replaceable; I model one AA
Battery life	1+ year at 2 s update; up to 10 years at 10 s update
Protection	NEMA 4X
Enclosure	5.3 x 4.3 x 2.7 in (135 x 109 x 69 mm), 2.0 lb (1 kg)
Datasheet date	April 2025

Order code: meter plus probe

A complete system is a meter plus a probe, and the datasheet recommends calibrating them together. Meter codes are DST600 or DST640, then R for user-selectable resolution, I for international AA battery or NB for no battery (needed for air shipment of C-cell lithium batteries), and P for panel mount or Q for a quick disconnect on the meter.

Probe step	Codes printed in the datasheet
Process connection	01 1/2 in NPT; 02 3/4 in NPT; 03 to 06 3-A sanitary flange for 1 in to 3 in tubes; 07 1-1/4 in 18 swivel nut; 08 1/2 in NPSM swivel nut; 09 unthreaded transition fitting
Stem connection	A adjustable angle; B rigid bottom; C remote bottom connection
Stem type	2 welded; 3 spring loaded (connections 01 and 02 only, about 1 in travel, needs a thermowell)
Stem material	1 304 SS; 2 316L SS; both rated to 400 F (204 C)
Stem diameter	1 = 1/4 in; 2 = 3/8 in; 3 = 5/8 in stem with 7/16 in tapered bulb (connection 07, 304 SS only); 4 = 1/2 in stepped down to 1/4 in over the last 1.5 in
Stem length	1 in to 72 in, written 01X to 72X; fractions A = 1/4, B = 1/2, C = 3/4 in

Stock stem lengths for the tapered bulb are listed as 3.5, 6, 8, 9, 12, 15, 18, 24, 30, 36, 42, 48, 54, 60, 66 and 72 inches. A NIST certificate is purchased separately.

Selection and installation

Choose the DST640 when the case will see washdown or RFI, and the DST600 for general benchtop and process use.
Use a welded probe for immersion, thermowells, sanitary or high-pressure service; use a spring loaded probe only with a thermowell, as the assembly is not sealed.
Specify the C battery for ground shipment, or the I or NB option for air freight, as the datasheet explains.
Plan for the DSTCAL calibration software if you need to adjust the sample rate, the R0 value or the calibration.
Order the meter and probe together so they can be calibrated as one system.

Applications in Oman and the GCC

The datasheet lists beverage processing, dairy processors, food processing, meat and poultry industries, pharmaceutical processing, retorts for low acid canned foods in hermetically sealed containers, and temperature critical applications generally. In the GCC this fits dairies, beverage plants, canneries, central kitchens and pharmaceutical production, where a record-quality readout beside the process is needed.

Selection and installation notes

A digital RTD thermometer depends on the probe attached, so confirm the probe length, diameter and connection before ordering. Insert the probe to the depth the maker advises, protect the cable and the connector, let the reading settle and check the instrument against a reference at regular intervals.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

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About brand

Palmer Wahl Instruments is a US maker of industrial temperature and pressure instruments based in Asheville, North Carolina. The company traces the Palmer name to Cincinnati, Ohio, in 1836 and Wahl Instruments to 1953; the two were combined in one Asheville facility.

Seven Star LLC is an independent supplier in Muscat. We list Palmer Wahl thermometers, calibrators and test instruments for maintenance and calibration teams in Oman and the GCC.

Palmer Wahl product series

Thermometers include the 1050 direct-drive 5-inch dial thermometer, the All Star bimetal thermometers in 3 and 5 inch sizes, the 9AL and 9FL economy industrial thermometers and the DST600 and DST640 Digi-Stem RTD thermometers. The DHS520L Heat Spy is a high-temperature infrared thermometer.

Calibration and test equipment includes the TC622A pocket RTD calibrator, the C150 documenting multifunction calibrator, the P32 handheld process signal calibrator, the HSICBB-P portable black body for checking infrared thermometers and the DSPG digital pressure gauge data logger.

Where Palmer Wahl instruments are used

Temperature indication on tanks, pipes and process equipment, field calibration of loops and temperature transmitters, infrared temperature checks on furnaces and kilns, and pressure logging during tests.

Ordering Palmer Wahl instruments: what we need

Send the instrument family, range, stem or probe length, process connection, case style and any calibration certificate or mercury-free requirement. The datasheet ordering guides allow the full code to be confirmed before an offer is issued.

Browse Palmer Wahl products by category: Portable Test & Measurement, Temperature Instrumentation.