This guide comprehensively covers digital temperature recorders. It first describes how these recorders work, and then explains what questions and factors you should consider before purchasing your own.
Digital temperature recorders were first introduced around 1990. Since then, they have evolved to eliminate many of the problems associated with mechanical strip chart recorders. As their technology has advanced, so too has their marketing. Twenty years ago, producers/shippers typically placed the least expensive strip chart recorder they could find on their shipments. Now, many perishable product buyers specify to their suppliers exactly which brand of temperature recorder to place on their orders. This exclusivity lets receivers improve efficiency (and reduce costs) by designing their protocols around the features and benefits of a single manufacturer’s technology.
Many digital recorders currently on the market use thermistor technology. Unlike the bi-metallic coil technology in strip chart recorders, a thermistor is a solid state electronic component that is sensitive to temperature. As ambient temperature drops, electrical current through the thermistor is slowed due to increased resistance. Warmer temperatures reduce the electrical resistance and allow more of the current through the thermistor. A simple integrated circuit measures resistance against a constant, and makes the temperature calculation based on that difference. Thermistor technology does not require any recalibration during its lifecycle and is accurate to 1/10th of 1 degree Fahrenheit in most applications.
Due to the wide range of temperature recorder applications, manufacturers have customized their recorders, product standards, interfaces, and supporting software packages for specific applications. While such customization is often essential, it has created a market environment in which cross-platform compatibility does not exist. Think Microsoft vs. Apple. A recorder from manufacturer “A” is NOT compatible with the supporting software from manufacturer “B” and visa-versa. Additionally, some units require use of proprietary cords, adapters, or other custom peripherals to download data from the instruments.
Some of the features available on digital recorders include LED “out of range” indicators, built-in LCDs which display summary reports, range programming selectors, audible beepers to help locate the recorder within a shipment, Radio Frequency (RF) transceivers, and even NFC technology which enables wireless data transfer to smartphones.
Contemporary technology has made “real-time” temperature and location monitoring a reality. Such systems enable online access to a shipments approximate current location, temperature, and door status. Real-time systems can also be configured to issue alerts if a shipment breaches preset temperature ranges, or other criteria.
Given the wide variety of features and technologies available, it is important to fully understand the needs of your specific application, and to choose your temperature monitoring instruments accordingly.
How long is your transit cycle? Digital recorders are typically available in recording periods ranging from 6 days to 80 days. Generally, it is best to use a recorder with a recording period closest to your needs. Since digital temperature recorders have only limited memory, longer recording period units take less frequent temperature samples to accommodate limited data storage capacity.
Single-Use or Reusable? The vast majority or temperature recorders are placed in vehicles/vessels that are one-way only (from supplier to purchaser). In this case, a single use recorder makes the most sense, since there is no cost effective means to return the recorder to the shipping point for re-use. In some closed-loop applications, such as intercompany transfers, a more expensive, reusable recorder can be a cost-saving option. An internal procedure would need be needed to download data and reset the recorder for its next use.
Do you require a real-time temperature monitoring instrument? Some commodities and/or shipments justify use of the more expensive, real-time monitoring instruments. In addition to providing real-time location and temperature status, these systems automatically save all data to the cloud without any human intervention. This is particularly valuable for Food Safety, Quality Assurance, or regulatory compliance programs.
Does your application include a wet environment? Some manufactures provide a waterproof pouch or other measure which can protect the recorder from harmful water fouling in transit. This is important when monitoring iced cargo like broccoli or corn. If an unprotected recorder falls off a pallet of iced product, it may be rendered inoperative by melting ice.
Would your Receiving/QA operations benefit from a smart device interface? Cargo Data Corporation’s Lightning NFC devices display the full temperature chart on the screen of an ordinary smartphone or tablet. The Lightning App also provides easy touch-screen data entry for product quality attributes and even the inclusion of product pictures. The Lightning NFC system can be used as a comprehensive QA and Food Safety tool to document perishable arrivals.
Can your operations benefit from cloud-based online data access? In most cases, when a shipment arrives showing temperature abuse, the Receiver/QA inspector notifies the product’s buyer. The buyer then contacts the supplier, who subsequently notifies the transportation broker/provider, who then calls the carrier/driver. Each party to the transaction wants a copy of the temperature chart to protect his/her interest in the transaction. The most common method of distributing this information is for the receiver to manually email or fax temperature recorder data to everyone. Frequently, this process is delayed while the receiver attends to other high priority arrivals on the dock.
The inefficiency of this process can be easily addressed with a cloud-based data archive which allows all interested parties access to non-editable temperature data online. Online data access is particularly helpful for overseas arrivals—no need to initiate email exchanges or battle language barriers. Cloud based data also eliminates the need to file hard copy temperature charts for each arrival. This feature alone can save many, many hours of back office labor.
Can your operation benefit from automation? Many larger scale perishables receivers have determined that operations can be streamlined with the implementation of automated temperature data collection and archiving systems. Temperature monitoring systems using NFC technology provide such automation. Similarly, some recorders manufactures have developed fully automated data archiving systems that don’t require any staff inputs, using cloud based storage as described above.
Would a digital temperature recorder with audible locating beeper bring efficiency to the receiving process? Some instruments are available with an audible locating beeper. A beeper can immediately alert receiving staff to the location of the devices and subsequently expedite the receiving process. This feature is generally NOT desired when shipments are sent overseas or via domestic package handlers like UPS and FedEx. Security protocols often require shipments with audible beepers to be opened and inspected. Recorders equipped with locating beepers are best suited to domestic over-the-road truckload and intermodal shipments.
What are your data archiving and reporting requirements? Digital temperature recorders are optimized to interface with PC based software packages. Some of the software is free, with no registration required, while some manufacturers restrict access through fee structures or registration requirements. Some manufacturers offer software packages that include only limited report generating capabilities, while others offer more robust reporting. Some apps can provide data in .pdf or in .csv (which is compatible with MS Excel) or proprietary formats. Some manufacturers offer summary printed reports from a central data center for additional costs.
Determine what reports you need (for internal and third party audit purposes), and confirm that the software and/or print services offered for your temperature monitoring system can support that specific reporting requirement. Obviously, avoid additional cost software and printed reports whenever possible.
Rebates for Used Recorder Recycling: Some temperature recorder manufacturers have embraced and encouraged recorder recycling programs to help eliminate hazardous electronic component waste (most recorders contain lead, cadmium, mercury, and other pollutants). Some manufacturers have implemented rebate programs for receivers who return used recorders.
Costs: Temperature recorder unit prices vary according to manufacturer and feature sets. Like many other infrastructure related decisions, a “Big Picture” approach must be adopted when determining what temperature monitoring system best fits your operational structure and budget. Rebate programs for returned recorders can substantially reduce the total cost of your temperature monitoring program.
Typically, suppliers purchase and place the receiver’s preferred temperature recorder on each perishable shipment. Suppliers will variously mark up, recover costs, or not invoice for the cost of the recorder. Some Receivers pay half of the cost of the recorder, while others shift all recorder costs to the supplier as a “cost of doing business”. The Food Safety Modernization Act (FSMA) mandates, and Cargo Data recommends, that each party reach advance agreement with regard to temperature recorder arrangements.
Sources: Cargo Data Corporation (www.cargodatacorp.com) of Ventura, CA offers the Lightning NFC system designed to simplify cold chain monitoring at every level. Boomerang Reusable, Quality Blue, WalMart approved, other specialty temperature recorders, KoldLink App free full-featured desktop software, and much, much more.
As product quality, safety, FSMA, and traceability programs become more sophisticated and more important, perishables logistics and quality assurance professionals will be increasingly responsible for monitoring cold chain integrity. Many such professionals are seeking an integrated and automated temperature monitoring system that provides added efficiency, full data archiving, and easy data sharing. You should too.
For free temperature monitoring program consultations, contact Cargo Data Corporation: firstname.lastname@example.org or 800-338-8134.