SR4/SRP4 FAQ

Q: Can I measure water pressure with SR4 or SRP4 loggers?

A:No. The media should be non-corrosive gases and dry air.

Q: What is the difference between Gauge and Absolute?

A: Gauge pressure is Zero PSI at atmospheric pressure.

Absolute pressure includes the atmospheric pressure. So, typically with no pressure applied, it will read approximately 14.7 PSI.

Absolute pressure = Gauge pressure + atmospheric pressure (for example: if the atmospheric pressure where you are is 14.7 PSI and your gauge pressure is 1 PSI then the Absolute pressure will be 15.7 PSI).

Q: Which logger should I use to measure atmospheric pressure?

A: You can use SRP-004-30A or SR-004-30A loggers.

Q: What is the accuracy of SR4 and SRP4 loggers?

 A: The accuracy of the pressure channels is +/-1% of full scale at 25°C (77°F) for the SmartReader 4 logger and +/-0.5% of full scale for the SmartReader Plus 4.  This only applies over the range of 0-70°C (32 to 160°F), as the pressure modules require temperature compensation.

Q: I want to record pressure values around 500 PSI. Do you have any pressure loggers for that range?

A: The maximum pressure range for the SRP4 is 150PSI Gauge. If you have a pressure transducer with the output of 0-25 mADC, or 0-200 mVDC, 0-2.5, 5, 10 Volt DC, then you can connect it to the SR7 or SRP7 (process signal logger). You can also write a custom equation to convert the unit and get the pressure readings in the required units (e.g. PSI).

Q: What type of pressure sensor does the SRP4 LPD Logger have?

A: It is a Silicon piezoresistive strain gauge.

Q: What is the accuracy of the SRP4 LPD loggers?

A: ±0.05”WC (±12.5Pa) for the ±2”, ±1” & ±0.5”WC ranges; ±0.1”WC (±25Pa) for the ±5” & ±10”WC ranges.

Q: Can I use ACR Data Loggers to measure dry air vacuum pressure?

A: Yes, you can. A SmartReader 4 or SmartReader Plus 4 with an Absolute pressure sensor can be used to measure pressure in the negative direction up to one atmosphere. Click here for more details.