noob saibot
Member
Hi Guys and Gals,
I have an AST4600 Pressure sensor connected to an Allen-Bradley Micrologix 1200 PLC via the 1762-IF4 module.
The problem is that the sensor reads the correct output voltage when disconnected from the PLC, but gets "pinned down" in voltage when connected.
Lets say I have 5800psi on the sensor, it will read 4.127V with the sensor disconnected which is just fine. When I connect it I read 3.083V at that same pressure, which is wrong. When I reduce the pressure on the sensor, it remains at 3.083V until I get to 3800psi in which it will read correctly and give me the correct voltage that I can translate to the correct pressure. So its basically Translating any pressure above 3800psi to 3.083V when the sensor is connected to the input module.
What is going on here? I had the same problem when trying to use small voltage dividers (potentiometer and resistor to adjust voltage) to simulate a pressure sensor on the 1762-IF4 input, however it worked with a benchtop power supply using the voltage. I have called AST and they can't seem to see any reason for it.
The specs of the sensor are:
10-28VDC Excitation
1-5V output (0-7500psi)
output impedance <100ohms, nominal
current consumption <10mA
Bandwidth (-3dB): DC to 1kHz
Output Noise <2mV RMS
Output load 5k Ohms Min.
Thanks in advance....
I have an AST4600 Pressure sensor connected to an Allen-Bradley Micrologix 1200 PLC via the 1762-IF4 module.
The problem is that the sensor reads the correct output voltage when disconnected from the PLC, but gets "pinned down" in voltage when connected.
Lets say I have 5800psi on the sensor, it will read 4.127V with the sensor disconnected which is just fine. When I connect it I read 3.083V at that same pressure, which is wrong. When I reduce the pressure on the sensor, it remains at 3.083V until I get to 3800psi in which it will read correctly and give me the correct voltage that I can translate to the correct pressure. So its basically Translating any pressure above 3800psi to 3.083V when the sensor is connected to the input module.
What is going on here? I had the same problem when trying to use small voltage dividers (potentiometer and resistor to adjust voltage) to simulate a pressure sensor on the 1762-IF4 input, however it worked with a benchtop power supply using the voltage. I have called AST and they can't seem to see any reason for it.
The specs of the sensor are:
10-28VDC Excitation
1-5V output (0-7500psi)
output impedance <100ohms, nominal
current consumption <10mA
Bandwidth (-3dB): DC to 1kHz
Output Noise <2mV RMS
Output load 5k Ohms Min.
Thanks in advance....