FAQ
In the process of assisting customers who have purchased the Trac-Stat SL1, we have answered a number of questions that may be of interest to other users or to companies considering a purchase. If your question is not answered below, please don't hesitate to contact us.
Do you sell the Trac-Stat SL1 in [Country]?
Does the SL1 need to have a computer connected to it?
Does the SL1 require a power source?
Can I remotely operate the SL1?
Does the SL1 provide a (RS-232 / RS-485 / Ethernet / SPI / I2C) interface?
What is the IEC Ingress Protection (IP) rating of the SL1?
What is the sampling period of the SL1?
How do I know that the SL1 is aligned to my tracker?
When I try to take a sample with the SL1, I get ERROR 20002.
Is my device defective?
Do I need the SL1 LabVIEW Driver Package in order to use the SL1 with LabVIEW?
Is a recalibration service available?
Who should I contact for additional technical questions or support on my Trac-Stat SL1 purchase?
Do you sell the Trac-Stat SL1 in [Country]?
Yes, we have been selling and shipping the SL1 worldwide, including customers on three continents to date. Note that we do require prepayment on all international shipments.
Does the SL1 need to have a computer connected to it?
No, the SL1 can be configured in an automatic (standalone) mode where it records sun data on some pre-set period.
Does the SL1 require a power source?
Yes, the SL1 must either be powered over the USB port (by connection to an on-site computer), or with a DC voltage source between 5 and 24V. A power supply, solar panel, or battery could be used to power the SL1. GreenMountain provides a cable terminated with the appropriate weatherproof connector and information on the connector (a standard off-the-shelf component available from Digikey and other vendors).
Can I remotely operate the SL1?
Included with the SL1 is a 2-meter weather-proof USB cable which allows serial communication, setup, and operation of the SL1 via a command-line interface. The SL1 can also be set to run in standalone datalogging mode, or canprovide error information as a set of analog voltages (for integration into the customer’s datalogger).
If you want to use the sensor interactively over the USB interface but remotely (at a distance greater than 2 meters), there are several options:
Replacement USB cables may extend operation up to 5 meters without the need of a repeater or extender.
USB booster cables are readily available and can extend the USB signal by an additional 5 meters (more if daisy-chained together). USB-over-Cat5 (Ethernet) extension kits are relatively inexpensive and we have successfully used one up to a distance of 150 meters, though typical kits are not designed for outdoor use. NOTE: Powering the SL1 through a USB-over-Cat5 extension is not recommended. Since drivers for the SL1 USB port are built into the Linux kernel, a small single-board computer in a weatherproof case could be used to get data from the SL1 and communicate via Ethernet to a remote controller.
GreenMountain is considering offering a weatherproof version of a USB-over-Cat5 converter as an accessory if there is sufficient interest.
Replacement USB cables may extend operation up to 5 meters without the need of a repeater or extender.
Does the SL1 provide a (RS-232 / RS-485 / Ethernet / SPI / I2C) interface?
Not at the current time, though we are collecting comments on the desired interface options and considering adding this functionality in a future product.
What is the IEC Ingress Protection (IP) rating of the SL1?
The SL1’s case is IP67-rated. The rating, though not identical, is comparable to a NEMA Type 6 enclosure rating. In addition, several SL1 units have been tested in the field through a month of heavy rain without problems.
What is the sampling period of the SL1?
There are two components to this answer.
First, the SL1 has a “sample period” configurable via the USB interface that sets how often it locates the sun, reports the pointing error, and saves this value to the internal nonvolatile memory. This period can be set to a wide range of values (we find many customers use 30-60 seconds), but typically can not be set to any shorter than 5-15 seconds, depending on other sensor settings. This time limitation is due to various algorithms and stabilization routines performed on the sensor for each reading.
However, the portion of this time spent acquiring of the sun position itself is much shorter, less than a second at the very beginning of the sampling period, so there is no need to worry about the sun moving significantly during the reading.
How do I know that the SL1 is aligned to my tracker?
You have multiple options:
1. The SL1 case provides several precision-machined reference surfaces, and has been factory-calibrated to be accurate relative to these mounting surfaces. As long as there is a surface on the tracker or module array which is flat and well-aligned to the tracker or the CPV optical axis, you can just mount the SL1 on this surface and immediately begin taking accurate data.
2. In case the tracker provides no flat or parallel mounting surfaces, the SL1 also provides a “software calibration” (zero offset) option. See the user manual for more details.
When I try to take a sample with the SL1, I get ERROR 20002. Is my device defective?
No, your sensor is not defective. ERROR 20002 (as well as ERROR 20007) simply indicates that the sun was not successfully located on one or both of the SL1’s individual sensors. This is commonly seen on the narrow angle sensor when the SL1 is pointed more than 2 degrees away from the sun.
See the Trac-Stat SL1 User Manual section 6.4 for further information. Future versions of the firmware will provide more of an explanation in the error message.
Do I need the SL1 LabVIEW Driver Package in order to use the SL1 with LabVIEW?
No, the SL1 LabVIEW Driver Package [available here] is not required for communication between LabVIEW and the SL1. The driver package may help save development time, but serial communication with the SL1 can be achieved using standard LabVIEW serial communication tools such as 'VISA Read' and 'VISA Write'.
When I try to set the START and STOP data logging hours according to the directions in the help menu (with ‘h 0 5’, for example) I am not getting the desired response. What’s going on?
There is a typo in the help menu of Firmware version 1.0.9. It should instead read:
h [*][*] -- View/set start/stop datalogging hours
[1=STARTHR, 2=STOPHR][NewHour, 0-23]
Is a recalibration service available for the Trac-Stat SL1?
GreenMountain provides an annual recalibration service from our lab in the US. For more information, or to schedule your annual calibration, please contact support@greenmountainengineering.com
Who should I contact for technical questions or support on my SL1 purchase?
You may contact us by e-mail at support@greenmountainengineering.com.