Lenze Global Drive PLC Developer Studio - Manual (Page 9)

LenzeFpiDrv.lib function library
General information about the RS−232C interface
2−2
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LenzeFpiDrv.lib EN 1.1
2.2 Electrical features
2.2.1 Voltage level
The logical states of the individual bits are sent as voltage states via send or receive cables:
Logical state Voltage level Min. voltage level − sender*
1 −3 ... −15 V −5 V
0 +3 ... +15 V +5 V
* at permissible ohmic load > 3 k W
The achievable distance between two RS−232C devices depends on the cable and baud rate used.
We recommend not to exceed a distance of 15 to 30 meters at a baud rate of 9600 baud.
2.2.2 Baud rate/data transmission rate
The baud rate indicates how many bits are transferred per second. This figure together with the other
transmission parameters (number of stop bits/data bits and parity bit) result in the data transmission
rate which is usually indicated in characters per second.
Transmission rate +
Baud rate
Total number of bits transmitted per character
Example
Transmission rate +
9600
1 (start bit) + 8 (data bits) + 1 (parity bit) + 1 (stop bit)
+ 872 characters/s
The following table indicates the data transmission rates possible when using a FP interface for a
transmission with 8 data bits, 1 stop bit and even parity.
Baud rate*
(Bit/s)
Transmission time per character
(ms)
Data transmission rate
(characters/s)
600 18.33 54
1200 9.17 109
2400 4.58 218
4800 2.29 436
9600 1.15 872
19200 0.573 1745
38400 0.286 3490
* With the FP interface every 250 ms a character can be sent, therefore a baud rate higher than 38400 baud cannot be recommended.