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RS323 to 485 converter as an programming cable.

Created by: Fran at: 11/30/2007 1:17 PM (1 Replies)

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11/30/2007 1:17 PM	Rate (0)
Fran Posts: 26 Rating: (1)	Hi all S7-200 users! I have searched FAQ's about this but i couldn't find a convincinganswer, so... I'm a rookie inRSxxx interfaces and maybe I'm trying to do something impossible, or senseless. I have a S7 224XP which i need to connect to an Fargo Maestro GSM Modem. I have a PC/PPI cable and aAten RS232 to RS485 converter (IC 485). I'm using the PPI cable for programming the CPU and the Aten converter to connect the PLC to the GSM Modem. I want to do this way because i want to debug the PLC-MODEM communication with the PC without buying and aditional PPI/PC cable. The Aten converter has a terminal blockwith four pins: R+, R-, T+, T- and an aditional ground i wired from the DB25plug input. Ihave built a cablefor connectingto the PLC port 0. According to the S7200 user's manual and Aten converter manuali wired the R- and T- output to the pin 8 of the PLC port (signal A) and the R+ and T+ output to the pin3 of the PLC port (signal B). The ground signal is wired too. This is Point-to-Point 2 wire half duplex configuration. To test the circuit i tried to communicate the PC to the S7 224 with this fittings (DCE mode for Aten converter). However, when refresh in the "communications" screen i get 127 unknown devices... even if i unplug the PLC (only with the Aten converter). This setting is only testing purpouse only. In the future the PC/PPI wil be used for PLC programming/debuging and the Aten converter for connecting the MODEM to the PLC. The question is i don't know if i built the cable wrong , or the PC/PG configuration. PC/PG interface is set to the same functional settings of the PC/PPI cable. I'm using Step7/MicroWIN V4 + SP4. Any ideas? Thanks in advance!
Fran Posts: 26 Rating: (1)
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12/3/2007 11:26 AM	Rate (0)
CS Moderator Moderator Joined: 9/1/2005 Last visit: 11/5/2024 Posts: 4109 Rating: (195)	closed cause question posted twice. The second thread with the subject RS 232 to RS485 converter wiring question is published within the conference SIMATIC S7-200. Best regards CS Moderator
	My Forum is the place to personalize your profile, track your topics, and maintain content that interests you. Best regards CS Moderator
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