I am trying to hook up a Keyence Laser Displacement sensor to my Arduino for displaying on an LCD readout. The Keyence unit has an RS232 (9600,N,8,1) connection which communicates the laser sensors distance. If I connect this directly to my MAC (using Coolterm) I am able to receive the distance data. If I connect the Keyence to my TTL/RS232 Adapter to my Arduino, the Arduino does not receive anything.
Trouble shooting steps I have already taken:
-I've connected the MAC/RS232 directly to the MAX232/Arduino and can get bidirectional communication no problem.
-I've looped the CTS/RTS and DCD/DSR outputs on the Keyence RS232 connector so the only wires going to the Arduino are Transmit, Receive, and ground.
-I've tried 2 different manufacturers of TTL-RS232
During troubleshooting I had it working for a fraction of a second when I had both the Arduino and MAC connected to the Keyence using a DB9 loop-through breakout adapter. I know RS232 is Pt to PT and this was not a great idea, but I was desperate for a solution. Everything so far has me feeling like the Keyence is looking for some voltage/signal it isn't getting from the TTL-RS232 adapter, but I am not experienced enough with RS232 to know what that is and what I am doing wrong.
Any help would be greatly appreciated - please let me know if I am leaving anything out.