RS-422 and RS-232C CableSection 2-2
2-1 | Power Supply and Cable Lengths |
Power Supply | For all but AL001 Link Adapters, connect the AC hot line to the common terminal |
| | of the Link Adapter. A fuse is internally connected to the common line. |
Cable Lengths | Maximum length for RS-232C cable is 15 m. For RS-422 it is 500 m, with a maxi- |
| | mum of 10 m for any given branch line. For RS-485 cable it is 200 m. |
| | Maximum lengths for optical fiber cables connected to Link Adapters are deter- |
| | mined by the type of cable and the particular model of Link Adapter employed. |
| | Link Adapters whose model numbers are followed by ª-Pº can be connected to |
| | either APF (all-plastic optical fiber) or PCF (plastic-clad optical fiber) cable. |
| | Those without ª-Pº can be connected only to PCF cable. The model numbers, |
| | cable types, and transmission distances are related as follows: |
| | | | | |
| | Cable | Model No. With P | Model No. Without P | |
| | | | | |
| | APF | 20 m | Not connectable | |
| | | | | |
| | PCF | 200 m | 800 m | |
If transmission distances over 800 meters are required, it is necessary to use AGF (crystal optical fiber) cable, which calls for the use of specific Link Adapters (see 1-4 General Specifications). For calculating maximum length for AGF cable, see 2-4 Crystal Optical Fiber Cable (AGF).
!Caution Never use a Link Adapter with its terminal cover removed. Keep the cover se- curely attached. If the Link Adapter is installed in an office or on a desk, take ex- tra care to avoid electrical shock.
2-2 RS-422 and RS-232C Cable
When using optical fiber or RS-422 cable, it is possible to connect several Host Link Units to one host computer. When RS-232C cable is used, however, the connection must either be on a one-to-one basis or a Link Adapter must be used to convert to optical or RS-422 cable. As described below, wiring will vary de- pending on whether a Host Link Unit is connected directly to a host computer or whether it is connected indirectly through a Link Adapter.
When a Host Link Unit is connected one-to-one to a host computer, with no Link Adapter, and RS-232C cable is being used, connect the SD (send data) terminal of the host computer to the RD (receive data) terminal of the Host Link Unit. Like- wise, connect the RD terminal of the host computer to the SD terminal of the Host Link Unit. When using RS-422 cable, the SDA and RDA terminals and the SDB and RDB terminals should be connected in a similar way. The following dia- gram illustrates the proper connections when using RS-232C cable.
Host computer
1 FG
7 SG
2SD
3RD
Pin No. Symbol
Host Link Unit
FG 1
SG 7
SD 2
RD 3
Symbol Pin No.
