Black Box ME500A, Руководство пользователя

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14
ASYNC/SYNC INDUSTRIAL LINE DRIVER
Switches S3-1 and S3-2: Input Impedance
The setting for Switches S3-1 and S3-2 determines the Line Driver’s input
impedance. This allows you to choose the optimum impedance setting for your
application. In long-distance applications, the impedance of the cable must match
the impedance of the load (or resistor) of the Async/Sync Industrial Line Driver.
Thicker-gauge cables require a lower-ohm setting, while a thinner-gauge cable
should receive a higher-ohm setting. If you are using higher speeds, you will need a
lower-ohm setting and a higher-ohm setting for the slower speeds. Refer to Table 3-
5 for assistance in selecting a setting.
S3-1 S3-2 Setting
On On 130 ohms
On Off 200 ohms
Off On 320 ohms
Off Off High impedance (minimum 2k ohms)
Table 3-5. Speed Selection
Cable Gauge Data Rates (kbps)
1.2 1.8 2.4 3.6 4.8 7.2 9.6 14.4
19 AWG/0.9 mm 320 320 200 200 200 200 200 130
22 AWG/0.6 mm 320 320 320 200 200 200 200 200
24 AWG/0.5 mm 320 320 320 320 200 200 200 200
26 AWG/0.4 mm 320 320 320 320 320 200 200 200
Cable Gauge Data Rates (kbps)
16 19.2 28.8 32 38.4 57.6 64
19 AWG/0.9 mm 130 130 130 130 130 High High
22 AWG/0.6 mm 200 130 130 130 130 High High
24 AWG/0.5 mm 200 200 130 130 130 High High
26 AWG/0.4 mm 200 200 200 200 130 High High
Switch S3-3: Timing-Mode Selection
Use Switch S3-3 to select the Line Driver’s timing mode. To operate the Line
Driver at 16, 32, or 64 kbps, set S3-3 to the On position. To select any other DTE
rate, set Switch S3-3 Off.
S3-3 Setting
On 16, 32, or 64 kbps
Off 1.2 through 57 kbps, excluding 16 and 32 kbps