mckruger Posted February 10, 2014 Report Share Posted February 10, 2014 Hi Everyone Hope you are all well. I am busy working on a mercedes engine using its PLD and ADM to communicate with it. The ADM on the vehicle give you outputs for oil pressure and coolant temprature etc. I have set my analog input to 0-10v and it is wired to receive a positive signal from the ADM. It does pick up a coolant temp but immediately goes back down to 0 value. When i take a VDO guage for temprature, it picks up the proper temprature and remains contant. I have also tried to set the analog input to 0-20m/a aswell as 4-20 m/a,. But it does the same thing. Is there something im doing wrong with the input as i know signal is coming through since the VDO guage works. Quote Link to comment Share on other sites More sharing options...
MVP 2014 Simon Posted February 10, 2014 MVP 2014 Report Share Posted February 10, 2014 Do you have a specification for the analogue outputs of the ADM (or the inputs on the VDO gauge)? Automotive signals don't usually play by the same rules as industrial signals. I would also try to measure the signal with a multimeter, starting on the voltage range. Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted February 10, 2014 MVP 2023 Report Share Posted February 10, 2014 Have you put a scope on the signal to see what happens when you connect the VDO gage vs the PLC? Which analog module are you using? What is the input impedance of the VDO? Could it be because the PLC analog input is common grounded and the VDO is floating or tied to the vehicle? Have you tied the PLC power supply common to the vehicle ground? Joe T. Quote Link to comment Share on other sites More sharing options...
mckruger Posted February 11, 2014 Author Report Share Posted February 11, 2014 I have ground the ADM/PLD to a common 12v. As the VDO guage is grounded to that when i was testing. The PLC is grounded to a 24v ground as the ADM/PLD are working on a 12v system. Specifications for Outputs from ADM Pin 12/3Oil Pressure Pin 12/04Coolant Temp Imax - 120 mA Umax - Ub Umin - 0v A) analog low side driver oil pressure guage, short protected low side switch for warning lamp Do not have a scope to test unfortunately. Using the V200-18-E46B snap-on Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted February 14, 2014 MVP 2023 Report Share Posted February 14, 2014 Connect the 24V ground to the 12V ground so you have a common reference. It won't hurt anything. Joe T. Quote Link to comment Share on other sites More sharing options...
mckruger Posted February 19, 2014 Author Report Share Posted February 19, 2014 Hi, Figured out that the actual output from the trucks ADM is giving off a resistance and not a voltage. I have to convert that from a resistance to a voltage in order for me to pick up a signal if im correct. Quote Link to comment Share on other sites More sharing options...
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