Why does my IN191 Blood FlowMeter show an output of -5 V on both channels?

When connecting a new flow probe to the Laser Doppler Blood FlowMeter and the readout on both the LDF and backscatter channels are -5 V, then the probe isn't recognized. Most likely you have purchased the probe separately or the probe was connected to a different unit before. You will need to calibrate the new probe to the Blood FlowMeter. Please note, probes shipped with a Blood FlowMeter are factory calibrated and do not require further calibration.
The Blood FlowMeter is designed to be easily configured and calibrated for new probes. This operation requires a Calibration Kit  (purchase separately), which includes a controlled concentration of latex spheres in suspension. Please note that the calibration solution has a use by date. Please follow the instructions provided with the Calibration Kit as calibration of probes is not possible without it and should not be attempted.