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SmartReader Plus 9 - Two-Channel Pulse Logger
Two-channel pulse/counter data logger for counting switch-contact closures or DC logic pulses. Each channel supports a “slow” (2 ms) or “fast” (10 µs) input and records up to 4,095 counts per sample interval. Accepts dry-contact switches or logic levels (Low 0–0.5 V, High 4.5–24 V), with a maximum signal frequency of 100 kHz. Available in 32 KB or 128 KB memory versions. Powered by a 3.6 V lithium battery; works with TrendReader software for Windows.
SKU: 01-0130
$1,262.00 USD
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Description Specifications Accessories Software Documentation Q&A Calibration

What it does

SmartReader Plus 9 (SRP-9) is a purpose-built counter/logger with two input channels for counting either contact-closure events or DC logic pulses. It’s commonly used to totalize or trend events such as flow-meter reed-switch closures, anemometer pulses, tipping-bucket rain gauges, RPM pickups, and watt-hour meter pulses. Each channel can be set to slow (2 ms) or fast (10 µs) operation. Per sample interval, the logger records up to 4,095 counts; if more occur, the interval is capped at 4,095.

Input types & thresholds

  • Dry contacts (unpowered “switch” inputs): The logger sources a very small current (~5 µA) at ~3.6 V across the terminals; use sealed gold-plated contacts where possible. Contacts must be dry (no external source across them).
  • Logic-level pulses: Low = 0–0.5 V DC; High = 4.5–24 V DC. Minimum pulse width/spacing: 2 ms (slow) or 10 µs (fast). Maximum signal frequency: 100 kHz.

Counting behavior

Counts are accumulated within each user-selected sample period and then stored to memory. Example: at a 16-second sample rate, the maximum average rate captured without clipping is 4,095 / 16 = 256 Hz (practically ~255 Hz). Choose a suitably short sample period for higher-rate signals.

Memory, rates, and software

  • Memory options: 32 KB (~21,500 readings) or 128 KB (~87,000 readings).
  • Sampling: from 25 samples/second up to once every 8 hours (external power required for rates faster than 1 sample/8 s).
  • Works with TrendReader® for Windows; connection via compatible USB/serial interface.

Physical & environmental

  • 12-bit stored readings; powered by a 3.6 V lithium battery.
  • Noryl® enclosure with magnetic backing/eyelet.
  • Operating limits: −40 °C to +70 °C; 0–95 % RH (non-condensing).
  • Approx. size/weight: 107 × 74 × 22 mm; 110 g.

When to choose SRP-9 vs SRP-8

Choose SRP-9 when you need counts per interval (e.g., totalizing or pulse-frequency trends). For on/off state logging (open/closed), consider our SRX8 Eight-Channel Thermistor (i.e. Resistance) Logger.

Compatibility notes (important)

  • Switch inputs must be dry (no external voltage across the contacts).
  • Logic pulses must meet the stated low/high thresholds and minimum pulse widths.
  • Maximum recordable counts per interval are capped at 4,095; select an appropriate sample period to avoid clipping.

Specifications

Accuracy +/- 1 pulse/sample period
Input Impedance greater than 1.0 M ohm for Vin less than 5V
greater than 4.0 K ohm for Vin less than 5V
Input Voltage Low = 0 to 0.5 volts DC
High = 4.5 to 24 volts DC
Maximum Frequency 100 KHz
Min. Pulse Width 50% Duty Cycle:
Slow input: 2 milliseconds
Fast input: 10 microseconds
Range 4095 pulses/sample period
Switch Inputs Input Type: Uncommitted “dry” contacts (relay or switch)
Excitation: 5 microamps contact current
3.6 volts open circuit
Contacts: Sealed gold-plated recommended
Warranty 3 – years

Accessories

Software & Interface Cable are required for full functionality of the product.

Weatherproof Box

Software

ACR software tools are intuitive and flexible, allowing you to easily configure ACR data loggers to collect the data you need. Once downloaded, your data is displayed in presentation-quality graphs and can be converted into popular formats for use with spreadsheet programs, document editors, and other third-party applications.

TrendReader Full License TrendReader Interface Pkg TrendReader on USB Full

Documentation

For a product sheet, please click below for a pdf version.

Product Sheet

A link to the Manual is available by clicking on the link below.

SmartReader Plus Manual

Q&A

Click here to visit our NEW Q&A pages.

Calibration

Data loggers are often used in highly regulated environments such as food and pharmaceutical production and storage where strict safety regulations apply. Regulatory agencies generally require proof of calibration.

ACR calibrations are performed using reference standards that have been calibrated and are traceable to the US National Institute of Standards & Technology (NIST). This ensures that all ACR data loggers meet, and perform to, their published specifications, allowing you to be confident that they will assist you in achieving your compliance requirements.

Calibration certificates are provided with every calibration we perform. ACR Systems is an ISO 9001:2015 registered company and calibration records are kept as part of our quality system and can be made available for customer audits.

Calibration Service

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Per sample interval, the logger records up to 4,095\u003cstrong\u003e \u003c\/strong\u003ecounts; if more occur, the interval is capped at 4,095.\u003c\/p\u003e\n\u003ch3\u003eInput types \u0026amp; thresholds\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDry contacts (unpowered “switch” inputs):\u003c\/strong\u003e The logger sources a very small current (~5 µA) at ~3.6 V across the terminals; use sealed gold-plated contacts where possible. Contacts must be dry (no external source across them).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLogic-level pulses:\u003c\/strong\u003e Low = 0–0.5 V DC; High = 4.5–24 V DC. Minimum pulse width\/spacing: 2 ms (slow) or 10 µs (fast). Maximum signal frequency: 100 kHz.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCounting behavior\u003c\/h3\u003e\n\u003cp\u003eCounts are accumulated within each user-selected sample period and then stored to memory. Example: at a 16-second sample rate, the maximum average rate captured without clipping is 4,095 \/ 16 = 256 Hz (practically ~255 Hz). Choose a suitably short sample period for higher-rate signals.\u003c\/p\u003e\n\u003ch3\u003eMemory, rates, and software\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMemory options: 32 KB (~21,500 readings) or 128 KB (~87,000 readings).\u003c\/li\u003e\n\u003cli\u003eSampling: from 25 samples\/second up to once every 8 hours (external power required for rates faster than 1 sample\/8 s).\u003c\/li\u003e\n\u003cli\u003eWorks with TrendReader® for Windows; connection via compatible USB\/serial interface.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePhysical \u0026amp; environmental\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e12-bit stored readings; powered by a 3.6 V lithium battery.\u003c\/li\u003e\n\u003cli\u003eNoryl® enclosure with magnetic backing\/eyelet.\u003c\/li\u003e\n\u003cli\u003eOperating limits: −40 °C to +70 °C; 0–95 % RH (non-condensing).\u003c\/li\u003e\n\u003cli\u003eApprox. size\/weight: 107 × 74 × 22 mm; 110 g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhen to choose SRP-9 vs SRP-8\u003c\/h3\u003e\n\u003cp\u003eChoose SRP-9 when you need counts per interval (e.g., totalizing or pulse-frequency trends). For on\/off state logging (open\/closed), consider our \u003ca href=\"\/products\/srx8-seven-channel-thermistor-temperature-logger\"\u003eSRX8 Eight-Channel Thermistor (i.e. Resistance) Logger\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eCompatibility notes (important)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSwitch inputs must be \u003cem\u003edry\u003c\/em\u003e (no external voltage across the contacts).\u003c\/li\u003e\n\u003cli\u003eLogic pulses must meet the stated low\/high thresholds and minimum pulse widths.\u003c\/li\u003e\n\u003cli\u003eMaximum recordable counts per interval are capped at 4,095; select an appropriate sample period to avoid clipping.\u003c\/li\u003e\n\u003c\/ul\u003e","published_at":"2020-12-18T20:41:59-08:00","created_at":"2020-12-18T20:41:59-08:00","vendor":"ACR Systems","type":"","tags":["SmartReader Plus Family"],"price":126200,"price_min":126200,"price_max":126200,"available":true,"price_varies":false,"compare_at_price":null,"compare_at_price_min":0,"compare_at_price_max":0,"compare_at_price_varies":false,"variants":[{"id":37804123914411,"title":"Default Title","option1":"Default Title","option2":null,"option3":null,"sku":"01-0130","requires_shipping":true,"taxable":true,"featured_image":null,"available":true,"name":"SmartReader Plus 9 - Two-Channel Pulse Logger","public_title":null,"options":["Default Title"],"price":126200,"weight":0,"compare_at_price":null,"inventory_management":null,"barcode":"","requires_selling_plan":false,"selling_plan_allocations":[]}],"images":["\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546","\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576"],"featured_image":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","options":["Title"],"media":[{"alt":null,"id":15547971764395,"position":1,"preview_image":{"aspect_ratio":1.257,"height":300,"width":377,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528"},"aspect_ratio":1.257,"height":300,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","width":377},{"alt":null,"id":15547973206187,"position":2,"preview_image":{"aspect_ratio":3.053,"height":131,"width":400,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546"},"aspect_ratio":3.053,"height":131,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546","width":400},{"alt":null,"id":15547974221995,"position":3,"preview_image":{"aspect_ratio":1.384,"height":289,"width":400,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576"},"aspect_ratio":1.384,"height":289,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576","width":400}],"requires_selling_plan":false,"selling_plan_groups":[],"content":"\u003ch3\u003eWhat it does\u003c\/h3\u003e\n\u003cp\u003eSmartReader Plus 9 (SRP-9) is a purpose-built counter\/logger with two input channels for counting either contact-closure events or DC logic pulses. It’s commonly used to totalize or trend events such as flow-meter reed-switch closures, anemometer pulses, tipping-bucket rain gauges, RPM pickups, and watt-hour meter pulses. Each channel can be set to \u003cem\u003eslow\u003c\/em\u003e (2 ms) or \u003cem\u003efast\u003c\/em\u003e (10 µs) operation. Per sample interval, the logger records up to 4,095\u003cstrong\u003e \u003c\/strong\u003ecounts; if more occur, the interval is capped at 4,095.\u003c\/p\u003e\n\u003ch3\u003eInput types \u0026amp; thresholds\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDry contacts (unpowered “switch” inputs):\u003c\/strong\u003e The logger sources a very small current (~5 µA) at ~3.6 V across the terminals; use sealed gold-plated contacts where possible. Contacts must be dry (no external source across them).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLogic-level pulses:\u003c\/strong\u003e Low = 0–0.5 V DC; High = 4.5–24 V DC. Minimum pulse width\/spacing: 2 ms (slow) or 10 µs (fast). Maximum signal frequency: 100 kHz.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCounting behavior\u003c\/h3\u003e\n\u003cp\u003eCounts are accumulated within each user-selected sample period and then stored to memory. Example: at a 16-second sample rate, the maximum average rate captured without clipping is 4,095 \/ 16 = 256 Hz (practically ~255 Hz). Choose a suitably short sample period for higher-rate signals.\u003c\/p\u003e\n\u003ch3\u003eMemory, rates, and software\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMemory options: 32 KB (~21,500 readings) or 128 KB (~87,000 readings).\u003c\/li\u003e\n\u003cli\u003eSampling: from 25 samples\/second up to once every 8 hours (external power required for rates faster than 1 sample\/8 s).\u003c\/li\u003e\n\u003cli\u003eWorks with TrendReader® for Windows; connection via compatible USB\/serial interface.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePhysical \u0026amp; environmental\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e12-bit stored readings; powered by a 3.6 V lithium battery.\u003c\/li\u003e\n\u003cli\u003eNoryl® enclosure with magnetic backing\/eyelet.\u003c\/li\u003e\n\u003cli\u003eOperating limits: −40 °C to +70 °C; 0–95 % RH (non-condensing).\u003c\/li\u003e\n\u003cli\u003eApprox. size\/weight: 107 × 74 × 22 mm; 110 g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhen to choose SRP-9 vs SRP-8\u003c\/h3\u003e\n\u003cp\u003eChoose SRP-9 when you need counts per interval (e.g., totalizing or pulse-frequency trends). For on\/off state logging (open\/closed), consider our \u003ca href=\"\/products\/srx8-seven-channel-thermistor-temperature-logger\"\u003eSRX8 Eight-Channel Thermistor (i.e. Resistance) Logger\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eCompatibility notes (important)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSwitch inputs must be \u003cem\u003edry\u003c\/em\u003e (no external voltage across the contacts).\u003c\/li\u003e\n\u003cli\u003eLogic pulses must meet the stated low\/high thresholds and minimum pulse widths.\u003c\/li\u003e\n\u003cli\u003eMaximum recordable counts per interval are capped at 4,095; select an appropriate sample period to avoid clipping.\u003c\/li\u003e\n\u003c\/ul\u003e"}
Translation missing: en.general.search.loading
{"id":6149855936683,"title":"SmartReader Plus 9 - Two-Channel Pulse Logger","handle":"smartreader-plus-9","description":"\u003ch3\u003eWhat it does\u003c\/h3\u003e\n\u003cp\u003eSmartReader Plus 9 (SRP-9) is a purpose-built counter\/logger with two input channels for counting either contact-closure events or DC logic pulses. It’s commonly used to totalize or trend events such as flow-meter reed-switch closures, anemometer pulses, tipping-bucket rain gauges, RPM pickups, and watt-hour meter pulses. Each channel can be set to \u003cem\u003eslow\u003c\/em\u003e (2 ms) or \u003cem\u003efast\u003c\/em\u003e (10 µs) operation. Per sample interval, the logger records up to 4,095\u003cstrong\u003e \u003c\/strong\u003ecounts; if more occur, the interval is capped at 4,095.\u003c\/p\u003e\n\u003ch3\u003eInput types \u0026amp; thresholds\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDry contacts (unpowered “switch” inputs):\u003c\/strong\u003e The logger sources a very small current (~5 µA) at ~3.6 V across the terminals; use sealed gold-plated contacts where possible. Contacts must be dry (no external source across them).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLogic-level pulses:\u003c\/strong\u003e Low = 0–0.5 V DC; High = 4.5–24 V DC. Minimum pulse width\/spacing: 2 ms (slow) or 10 µs (fast). Maximum signal frequency: 100 kHz.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCounting behavior\u003c\/h3\u003e\n\u003cp\u003eCounts are accumulated within each user-selected sample period and then stored to memory. Example: at a 16-second sample rate, the maximum average rate captured without clipping is 4,095 \/ 16 = 256 Hz (practically ~255 Hz). Choose a suitably short sample period for higher-rate signals.\u003c\/p\u003e\n\u003ch3\u003eMemory, rates, and software\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMemory options: 32 KB (~21,500 readings) or 128 KB (~87,000 readings).\u003c\/li\u003e\n\u003cli\u003eSampling: from 25 samples\/second up to once every 8 hours (external power required for rates faster than 1 sample\/8 s).\u003c\/li\u003e\n\u003cli\u003eWorks with TrendReader® for Windows; connection via compatible USB\/serial interface.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePhysical \u0026amp; environmental\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e12-bit stored readings; powered by a 3.6 V lithium battery.\u003c\/li\u003e\n\u003cli\u003eNoryl® enclosure with magnetic backing\/eyelet.\u003c\/li\u003e\n\u003cli\u003eOperating limits: −40 °C to +70 °C; 0–95 % RH (non-condensing).\u003c\/li\u003e\n\u003cli\u003eApprox. size\/weight: 107 × 74 × 22 mm; 110 g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhen to choose SRP-9 vs SRP-8\u003c\/h3\u003e\n\u003cp\u003eChoose SRP-9 when you need counts per interval (e.g., totalizing or pulse-frequency trends). For on\/off state logging (open\/closed), consider our \u003ca href=\"\/products\/srx8-seven-channel-thermistor-temperature-logger\"\u003eSRX8 Eight-Channel Thermistor (i.e. Resistance) Logger\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eCompatibility notes (important)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSwitch inputs must be \u003cem\u003edry\u003c\/em\u003e (no external voltage across the contacts).\u003c\/li\u003e\n\u003cli\u003eLogic pulses must meet the stated low\/high thresholds and minimum pulse widths.\u003c\/li\u003e\n\u003cli\u003eMaximum recordable counts per interval are capped at 4,095; select an appropriate sample period to avoid clipping.\u003c\/li\u003e\n\u003c\/ul\u003e","published_at":"2020-12-18T20:41:59-08:00","created_at":"2020-12-18T20:41:59-08:00","vendor":"ACR Systems","type":"","tags":["SmartReader Plus Family"],"price":126200,"price_min":126200,"price_max":126200,"available":true,"price_varies":false,"compare_at_price":null,"compare_at_price_min":0,"compare_at_price_max":0,"compare_at_price_varies":false,"variants":[{"id":37804123914411,"title":"Default Title","option1":"Default Title","option2":null,"option3":null,"sku":"01-0130","requires_shipping":true,"taxable":true,"featured_image":null,"available":true,"name":"SmartReader Plus 9 - Two-Channel Pulse Logger","public_title":null,"options":["Default Title"],"price":126200,"weight":0,"compare_at_price":null,"inventory_management":null,"barcode":"","requires_selling_plan":false,"selling_plan_allocations":[]}],"images":["\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546","\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576"],"featured_image":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","options":["Title"],"media":[{"alt":null,"id":15547971764395,"position":1,"preview_image":{"aspect_ratio":1.257,"height":300,"width":377,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528"},"aspect_ratio":1.257,"height":300,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2366_400_300.jpg?v=1610172528","width":377},{"alt":null,"id":15547973206187,"position":2,"preview_image":{"aspect_ratio":3.053,"height":131,"width":400,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546"},"aspect_ratio":3.053,"height":131,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2370_400_300.jpg?v=1610172546","width":400},{"alt":null,"id":15547974221995,"position":3,"preview_image":{"aspect_ratio":1.384,"height":289,"width":400,"src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576"},"aspect_ratio":1.384,"height":289,"media_type":"image","src":"\/\/www.acrdatasolutions.com\/cdn\/shop\/products\/2373_400_300.jpg?v=1610172576","width":400}],"requires_selling_plan":false,"selling_plan_groups":[],"content":"\u003ch3\u003eWhat it does\u003c\/h3\u003e\n\u003cp\u003eSmartReader Plus 9 (SRP-9) is a purpose-built counter\/logger with two input channels for counting either contact-closure events or DC logic pulses. It’s commonly used to totalize or trend events such as flow-meter reed-switch closures, anemometer pulses, tipping-bucket rain gauges, RPM pickups, and watt-hour meter pulses. Each channel can be set to \u003cem\u003eslow\u003c\/em\u003e (2 ms) or \u003cem\u003efast\u003c\/em\u003e (10 µs) operation. Per sample interval, the logger records up to 4,095\u003cstrong\u003e \u003c\/strong\u003ecounts; if more occur, the interval is capped at 4,095.\u003c\/p\u003e\n\u003ch3\u003eInput types \u0026amp; thresholds\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDry contacts (unpowered “switch” inputs):\u003c\/strong\u003e The logger sources a very small current (~5 µA) at ~3.6 V across the terminals; use sealed gold-plated contacts where possible. Contacts must be dry (no external source across them).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLogic-level pulses:\u003c\/strong\u003e Low = 0–0.5 V DC; High = 4.5–24 V DC. Minimum pulse width\/spacing: 2 ms (slow) or 10 µs (fast). Maximum signal frequency: 100 kHz.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCounting behavior\u003c\/h3\u003e\n\u003cp\u003eCounts are accumulated within each user-selected sample period and then stored to memory. Example: at a 16-second sample rate, the maximum average rate captured without clipping is 4,095 \/ 16 = 256 Hz (practically ~255 Hz). Choose a suitably short sample period for higher-rate signals.\u003c\/p\u003e\n\u003ch3\u003eMemory, rates, and software\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMemory options: 32 KB (~21,500 readings) or 128 KB (~87,000 readings).\u003c\/li\u003e\n\u003cli\u003eSampling: from 25 samples\/second up to once every 8 hours (external power required for rates faster than 1 sample\/8 s).\u003c\/li\u003e\n\u003cli\u003eWorks with TrendReader® for Windows; connection via compatible USB\/serial interface.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003ePhysical \u0026amp; environmental\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e12-bit stored readings; powered by a 3.6 V lithium battery.\u003c\/li\u003e\n\u003cli\u003eNoryl® enclosure with magnetic backing\/eyelet.\u003c\/li\u003e\n\u003cli\u003eOperating limits: −40 °C to +70 °C; 0–95 % RH (non-condensing).\u003c\/li\u003e\n\u003cli\u003eApprox. size\/weight: 107 × 74 × 22 mm; 110 g.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhen to choose SRP-9 vs SRP-8\u003c\/h3\u003e\n\u003cp\u003eChoose SRP-9 when you need counts per interval (e.g., totalizing or pulse-frequency trends). For on\/off state logging (open\/closed), consider our \u003ca href=\"\/products\/srx8-seven-channel-thermistor-temperature-logger\"\u003eSRX8 Eight-Channel Thermistor (i.e. Resistance) Logger\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eCompatibility notes (important)\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSwitch inputs must be \u003cem\u003edry\u003c\/em\u003e (no external voltage across the contacts).\u003c\/li\u003e\n\u003cli\u003eLogic pulses must meet the stated low\/high thresholds and minimum pulse widths.\u003c\/li\u003e\n\u003cli\u003eMaximum recordable counts per interval are capped at 4,095; select an appropriate sample period to avoid clipping.\u003c\/li\u003e\n\u003c\/ul\u003e"}